Merge pull request #96 from jpirnay/examine-memory-regression-master

refactor: fix memory regression due to Activity push

docs/activity-manager.md

@@ -11,6 +11,7 @@ This document explains the refactoring from the original per-activity render tas
 | `RenderLock` | Inner class of `Activity` | Standalone class, acquires global mutex |
 | Subactivities | `ActivityWithSubactivity` base class | Activity stack managed by `ActivityManager` |
 | Navigation | Free functions in `main.cpp` | `activityManager.goHome()`, `goToReader()`, etc. |
+| Forward flow | Parent stays on stack (`pushActivity`) | Parent destroyed on forward flow (`replaceWith*` + `ReturnHint`) |
 | Subactivity results | Callback lambdas stored in parent | `startActivityForResult()` / `setResult()` / `finish()` |
 | `requestUpdate()` | Notifies activity's own render task | Delegates to `ActivityManager` (immediate or deferred) |
 
@@ -99,7 +100,7 @@ class MyActivity final : public Activity {
 };
 ```
 
-Note that navigation callbacks like `goBack` are no longer stored — use `finish()` or `activityManager.goHome()` instead.
+Note that navigation callbacks like `goBack` are no longer stored — use `finish()`, `onGoHome()`, or a direct `activityManager.goHome()` / `goTo*()` / `replaceWith*()` call instead.
 
 ### 2. Replace Navigation Functions
 
@@ -116,7 +117,7 @@ activityManager.goToSettings();
 activityManager.replaceActivity(std::make_unique<MyActivity>(renderer, mappedInput));
 ```
 
-`replaceActivity()` destroys the current activity and clears the stack. Use it for top-level navigation (home, reader, settings, etc.).
+`replaceActivity()` destroys the current activity and clears the stack. Use it for top-level navigation (home, reader, settings, etc.). See the "Navigation Flow" section after the checklist for when to use replace vs push, and how the `ReturnHint` mechanism restores a parent's prior state without keeping it resident.
 
 ### 3. Replace Subactivity Pattern
 
@@ -234,12 +235,82 @@ class SettingsActivity : public Activity {
 public:
   SettingsActivity(GfxRenderer& r, MappedInputManager& m)
       : Activity("Settings", r, m) {}
-  // Use finish() to go back, activityManager.goHome() to go home
+  // Use finish() to go back (pops the stack, or returns via ReturnHint if empty),
+  // onGoHome() to exit the flow ("up and out"), or activityManager.goHome() for a hard reset.
 };
 ```
 
 This removes `std::function` overhead (~2-4KB per unique signature) and eliminates lifetime risks from captured `this` pointers.
 
+## Navigation Flow
+
+### Push vs Replace: Memory Matters
+
+On an ESP32-C3, heap fragmentation is a real constraint — especially when the next activity is heavy (EPUB reader, TLS sync). There are two ways to launch a new activity, and the choice matters:
+
+| Call                                               | Current activity                | Stack            | When to use                                                 |
+|----------------------------------------------------|---------------------------------|------------------|-------------------------------------------------------------|
+| `replaceActivity()` / `goTo*()` / `replaceWith*()` | **destroyed** (onExit + delete) | cleared          | Forward flow: the caller has no reason to stay resident     |
+| `pushActivity()` / `startActivityForResult()`      | kept alive on stack             | parent preserved | Modal result flow: the caller needs to resume with a result |
+
+**Default to replace.** Push is only correct when you need to deliver a result back to a still-living parent (keyboard entry, confirmation dialog, chapter picker, etc.). For plain one-way transitions — opening a book, going to settings, switching tabs — use replace so the parent's memory is freed before the next activity runs.
+
+### The `ReturnHint` Pattern
+
+Replace destroys the parent, but the user still expects Back to return "where they came from" — not always Home. To bridge that, `ActivityManager` holds a small `ReturnHint`:
+
+```cpp
+enum class ReturnTo : uint8_t { Home, FileBrowser, RecentBooks };
+
+struct ReturnHint {
+  ReturnTo target = ReturnTo::Home;
+  std::string path;        // FileBrowser directory to restore
+  std::string selectName;  // item to re-focus (file name, book path)
+  int selectIndex = -1;    // combined-list index (Home selector, Recents row)
+};
+```
+
+A parent records a hint before launching a forward flow. When the launched activity (or anything it chains to) eventually exits with an empty stack, `ActivityManager::returnFromChild()` consumes the hint and routes to the correct parent — restoring its prior selection. If no hint is set, it falls back to `goHome()`.
+
+Two ways to set a hint:
+
+**1. Dedicated wrappers** — for the common book-open paths:
+
+```cpp
+// FileBrowserActivity::onFileOpen
+ReturnHint hint;
+hint.target     = ReturnTo::FileBrowser;
+hint.path       = basepath;        // "/books/fiction"
+hint.selectName = entry;           // "war_and_peace.epub"
+activityManager.replaceWithReader(fullPath, std::move(hint));
+
+// RecentBooksActivity::onSelect
+ReturnHint hint;
+hint.target      = ReturnTo::RecentBooks;
+hint.selectIndex = selectorIndex;
+activityManager.replaceWithReader(path, std::move(hint));
+```
+
+**2. `setReturnHint()` + any `goTo*()`** — for arbitrary transitions where a dedicated wrapper would be overkill:
+
+```cpp
+// HomeActivity::dispatchMenuAction
+ReturnHint hint;
+hint.target      = ReturnTo::Home;
+hint.selectIndex = selectorIndex;   // restore focus on the same menu entry
+activityManager.setReturnHint(std::move(hint));
+activityManager.goToSettings();     // parent destroyed; hint survives the round trip
+```
+
+`goTo*()` helpers do **not** clear the hint — only `goHome()` (explicit hard-reset) and the `replaceWith*()` helpers (which overwrite it with their own hint) do. This lets a hint survive chained transitions: Home → Reader → KOReaderSync → Reader → back to Home, hint intact.
+
+How `finish()` interacts with the hint:
+
+- **Non-empty stack**: `finish()` pops to the parent on the stack (classic modal result flow). Hint is untouched.
+- **Empty stack**: `finish()` falls through to `returnFromChild()` automatically. An activity launched via a `replaceWith*()` helper has no stack — so its Back-button `finish()` naturally routes via the hint.
+
+`onGoHome()` is now semantically "up and out" — it calls `returnFromChild()`, so long-press Back in a reader returns to whichever view opened the book, not always Home. For an explicit hard-reset, call `activityManager.goHome()` directly.
+
 ## Technical Details
 
 ### FreeRTOS Task Model
@@ -444,6 +515,10 @@ Child calls: setResult(MyResult{...}); finish();
 
 **Creating background tasks that outlive the activity**: Any FreeRTOS task created in `onEnter()` must be deleted in `onExit()` before the activity is destroyed. The `ActivityManager` does not track or clean up background tasks.
 
+**Using push for forward navigation**: `pushActivity()` / `startActivityForResult()` keeps the parent alive on the stack. For a heavy child (EPUB reader, TLS sync) on a fragmented heap, the parent's resident allocations can be the difference between a successful launch and OOM. Only push when you need the parent to receive a result — otherwise use `replaceActivity()` / `goTo*()` / `replaceWith*()` and let the parent be freed first. If you do need "back to where I came from" semantics, record a `ReturnHint` before the replace instead of pushing.
+
+**Stale `ReturnHint`**: A hint set by one activity persists until either `returnFromChild()` / `goHome()` clears it, or a `replaceWith*()` helper overwrites it. If you record a hint but the flow aborts down an unusual path (error screen, boot transition), the next unrelated `finish()` could consume it. Prefer setting the hint immediately before the transition, and call `activityManager.clearReturnHint()` if you abort the flow without launching the intended target.
+
 **Holding `RenderLock` across blocking calls**: The render task is blocked on the mutex while you hold the lock. Keep critical sections short — acquire, mutate state, release, then do blocking work.
 
 ```cpp

src/SettingsList.h

@@ -34,21 +34,13 @@
 // deep inside the heap allocator chain — enough stack to overflow the 8 KB loop task stack
 // when called from inside SETTINGS.loadFromFile() at boot time.
 namespace SettingsListDetail {
-inline uint8_t getKoReaderMatchMethod(const void*) {
-  return static_cast<uint8_t>(KOREADER_STORE.getMatchMethod());
-}
+inline uint8_t getKoReaderMatchMethod(const void*) { return static_cast<uint8_t>(KOREADER_STORE.getMatchMethod()); }
 
-inline std::string getKoReaderServerUrl(void*) {
-  return KOREADER_STORE.getServerUrl();
-}
+inline std::string getKoReaderServerUrl(void*) { return KOREADER_STORE.getServerUrl(); }
 
-inline std::string getKoReaderUsername(void*) {
-  return KOREADER_STORE.getUsername();
-}
+inline std::string getKoReaderUsername(void*) { return KOREADER_STORE.getUsername(); }
 
-inline std::string getKoReaderPassword(void*) {
-  return KOREADER_STORE.getPassword();
-}
+inline std::string getKoReaderPassword(void*) { return KOREADER_STORE.getPassword(); }
 
 inline const std::vector<SettingInfo> list = {
     // --- Display ---
@@ -167,24 +159,21 @@ inline const std::vector<SettingInfo> list = {
 
     // --- KOReader Sync (web-only, uses KOReaderCredentialStore) ---
     SettingInfo::DynamicString(
-        StrId::STR_SYNC_SERVER_URL,
-        static_cast<SettingInfo::StringGetterFn>(getKoReaderServerUrl),
+        StrId::STR_SYNC_SERVER_URL, static_cast<SettingInfo::StringGetterFn>(getKoReaderServerUrl),
         [](void*, const std::string& v) {
           KOREADER_STORE.setServerUrl(v);
           KOREADER_STORE.saveToFile();
         },
         "koServerUrl", StrId::STR_KOREADER_SYNC),
     SettingInfo::DynamicString(
-        StrId::STR_KOREADER_USERNAME,
-        static_cast<SettingInfo::StringGetterFn>(getKoReaderUsername),
+        StrId::STR_KOREADER_USERNAME, static_cast<SettingInfo::StringGetterFn>(getKoReaderUsername),
         [](void*, const std::string& v) {
           KOREADER_STORE.setCredentials(v, KOREADER_STORE.getPassword());
           KOREADER_STORE.saveToFile();
         },
         "koUsername", StrId::STR_KOREADER_SYNC),
     SettingInfo::DynamicString(
-        StrId::STR_KOREADER_PASSWORD,
-        static_cast<SettingInfo::StringGetterFn>(getKoReaderPassword),
+        StrId::STR_KOREADER_PASSWORD, static_cast<SettingInfo::StringGetterFn>(getKoReaderPassword),
         [](void*, const std::string& v) {
           KOREADER_STORE.setCredentials(KOREADER_STORE.getUsername(), v);
           KOREADER_STORE.saveToFile();
@@ -192,8 +181,7 @@ inline const std::vector<SettingInfo> list = {
         "koPassword", StrId::STR_KOREADER_SYNC)
         .withObfuscated(),
     SettingInfo::DynamicEnum(
-        StrId::STR_DOCUMENT_MATCHING, {StrId::STR_FILENAME, StrId::STR_BINARY},
-        getKoReaderMatchMethod,
+        StrId::STR_DOCUMENT_MATCHING, {StrId::STR_FILENAME, StrId::STR_BINARY}, getKoReaderMatchMethod,
         [](void*, uint8_t v) {
           KOREADER_STORE.setMatchMethod(static_cast<DocumentMatchMethod>(v));
           KOREADER_STORE.saveToFile();

src/activities/Activity.cpp

@@ -10,9 +10,9 @@ void Activity::requestUpdate(bool immediate) { activityManager.requestUpdate(imm
 
 void Activity::requestUpdateAndWait() { activityManager.requestUpdateAndWait(); }
 
-void Activity::onGoHome() { activityManager.goHome(); }
-
-void Activity::onSelectBook(const std::string& path) { activityManager.pushReader(path); }
+// "Up and out" — return to whichever parent launched this flow. If no return hint
+// is set (typical for activities launched via a plain goTo*()), falls back to Home.
+void Activity::onGoHome() { activityManager.returnFromChild(); }
 
 void Activity::startActivityForResult(std::unique_ptr<Activity>&& activity, ActivityResultHandler resultHandler) {
   this->resultHandler = std::move(resultHandler);

src/activities/Activity.h

@@ -27,6 +27,7 @@ class Activity {
   explicit Activity(std::string name, GfxRenderer& renderer, MappedInputManager& mappedInput)
       : name(std::move(name)), renderer(renderer), mappedInput(mappedInput) {}
   virtual ~Activity() = default;
+  const std::string& getName() const { return name; }
   virtual void onEnter();
   virtual void onExit();
   virtual void loop() {}
@@ -57,5 +58,4 @@ class Activity {
   // Convenience method to facilitate API transition to ActivityManager
   // TODO: remove this in near future
   void onGoHome();
-  void onSelectBook(const std::string& path);
 };

src/activities/ActivityManager.cpp

@@ -3,6 +3,9 @@
 #include <Arduino.h>
 #include <HalClock.h>
 #include <HalPowerManager.h>
+#include <Logging.h>
+#include <esp_heap_caps.h>
+#include <esp_system.h>
 
 #include "CrossPointState.h"
 #include "boot_sleep/BootActivity.h"
@@ -19,6 +22,10 @@
 #include "util/FullScreenMessageActivity.h"
 #include "weather/WeatherActivity.h"
 
+#ifndef DEBUG_MEMORY_CONSUMPTION
+#define DEBUG_MEMORY_CONSUMPTION 0
+#endif
+
 void ActivityManager::begin() {
   xTaskCreate(&renderTaskTrampoline, "ActivityManagerRender",
               8192,              // Stack size
@@ -29,6 +36,17 @@ void ActivityManager::begin() {
   assert(renderTaskHandle != nullptr && "Failed to create render task");
 }
 
+#if DEBUG_MEMORY_CONSUMPTION
+static void logActivityStackState(const char* stage, Activity* currentActivity, size_t stackSize) {
+  const uint32_t freeHeap = esp_get_free_heap_size();
+  const uint32_t contigHeap = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT | MALLOC_CAP_DEFAULT);
+  LOG_DBG("ACT", "%s: current=%s stackSize=%zu free=%lu contig=%lu", stage,
+          currentActivity ? currentActivity->getName().c_str() : "<none>", stackSize, freeHeap, contigHeap);
+}
+#else
+static inline void logActivityStackState(const char*, Activity*, size_t) {}
+#endif
+
 void ActivityManager::renderTaskTrampoline(void* param) {
   auto* self = static_cast<ActivityManager*>(param);
   self->renderTaskLoop();
@@ -111,10 +129,10 @@ void ActivityManager::loop() {
       pendingAction = PendingAction::None;
 
       if (stackActivities.empty()) {
-        LOG_DBG("ACT", "No more activities on stack, going home");
-        lock.unlock();  // goHome may acquire its own lock
-        goHome();
-        continue;  // Will launch goHome immediately
+        LOG_DBG("ACT", "No more activities on stack, returning from child");
+        lock.unlock();  // returnFromChild may acquire its own lock via replaceActivity
+        returnFromChild();
+        continue;  // Will launch the target activity immediately
 
       } else {
         currentActivity = std::move(stackActivities.back());
@@ -149,6 +167,9 @@ void ActivityManager::loop() {
       RenderLock lock;
 
       if (pendingAction == PendingAction::Replace) {
+#if DEBUG_MEMORY_CONSUMPTION
+        logActivityStackState("replace_before", currentActivity.get(), stackActivities.size());
+#endif
         // Destroy the current activity
         exitActivity(lock);
         // Clear the stack
@@ -156,10 +177,21 @@ void ActivityManager::loop() {
           stackActivities.back()->onExit();
           stackActivities.pop_back();
         }
+#if DEBUG_MEMORY_CONSUMPTION
+        logActivityStackState("replace_after_clear", nullptr, stackActivities.size());
+#endif
       } else if (pendingAction == PendingAction::Push) {
+#if DEBUG_MEMORY_CONSUMPTION
+        logActivityStackState("push_before", currentActivity.get(), stackActivities.size());
+#endif
         // Move current activity to stack
         stackActivities.push_back(std::move(currentActivity));
+#if DEBUG_MEMORY_CONSUMPTION
         LOG_DBG("ACT", "Pushed to activity stack, new size = %zu", stackActivities.size());
+        logActivityStackState("push_after", currentActivity.get(), stackActivities.size());
+#else
+        LOG_DBG("ACT", "Pushed to activity stack, new size = %zu", stackActivities.size());
+#endif
       }
       pendingAction = PendingAction::None;
       currentActivity = std::move(pendingActivity);
@@ -201,6 +233,10 @@ void ActivityManager::replaceActivity(std::unique_ptr<Activity>&& newActivity) {
   if (currentActivity) {
     // Defer launch if we're currently in an activity, to avoid deleting the current activity
     // leading to the "delete this" problem
+#if DEBUG_MEMORY_CONSUMPTION
+    LOG_DBG("ACT", "replaceActivity requested: current=%s stackSize=%zu", currentActivity->getName().c_str(),
+            stackActivities.size());
+#endif
     pendingActivity = std::move(newActivity);
     pendingAction = PendingAction::Replace;
   } else {
@@ -216,16 +252,19 @@ void ActivityManager::goToFileTransfer() {
 
 void ActivityManager::goToSettings() { replaceActivity(std::make_unique<SettingsActivity>(renderer, mappedInput)); }
 
-void ActivityManager::goToFileBrowser(std::string path) {
-  replaceActivity(std::make_unique<FileBrowserActivity>(renderer, mappedInput, std::move(path)));
+void ActivityManager::goToFileBrowser(std::string path, std::string focusName) {
+  replaceActivity(std::make_unique<FileBrowserActivity>(renderer, mappedInput, std::move(path), std::move(focusName)));
 }
 
-void ActivityManager::goToRecentBooks() {
-  replaceActivity(std::make_unique<RecentBooksActivity>(renderer, mappedInput));
+void ActivityManager::goToRecentBooks(int focusIndex) {
+  replaceActivity(std::make_unique<RecentBooksActivity>(renderer, mappedInput, focusIndex));
 }
 
-void ActivityManager::goToGlobalBookmarks() {
-  replaceActivity(std::make_unique<GlobalBookmarksActivity>(renderer, mappedInput));
+void ActivityManager::goToGlobalBookmarks() { goToGlobalBookmarks({}); }
+
+void ActivityManager::goToGlobalBookmarks(ReturnHint hint) {
+  hasReturnHint = false;
+  replaceActivity(std::make_unique<GlobalBookmarksActivity>(renderer, mappedInput, std::move(hint)));
 }
 
 void ActivityManager::goToBrowser() {
@@ -249,8 +288,48 @@ void ActivityManager::goToKOReaderSync() {
                                                          sync.hasParagraphIndex, sync.intent));
 }
 
-void ActivityManager::pushReader(std::string path) {
-  pushActivity(std::make_unique<ReaderActivity>(renderer, mappedInput, std::move(path)));
+void ActivityManager::replaceWithReader(std::string path, ReturnHint hint) {
+  returnHint = std::move(hint);
+  hasReturnHint = true;
+  replaceActivity(std::make_unique<ReaderActivity>(renderer, mappedInput, std::move(path)));
+}
+
+void ActivityManager::replaceWithFileBrowser(std::string path, ReturnHint hint, std::string focusName) {
+  returnHint = std::move(hint);
+  hasReturnHint = true;
+  replaceActivity(std::make_unique<FileBrowserActivity>(renderer, mappedInput, std::move(path), std::move(focusName)));
+}
+
+void ActivityManager::replaceWithRecentBooks(ReturnHint hint) {
+  returnHint = std::move(hint);
+  hasReturnHint = true;
+  replaceActivity(std::make_unique<RecentBooksActivity>(renderer, mappedInput, -1));
+}
+
+void ActivityManager::returnFromChild() {
+  if (!hasReturnHint) {
+    goHome();
+    return;
+  }
+  ReturnHint hint = std::move(returnHint);
+  returnHint = {};
+  hasReturnHint = false;
+
+  switch (hint.target) {
+    case ReturnTo::FileBrowser:
+      goToFileBrowser(std::move(hint.path), std::move(hint.selectName));
+      break;
+    case ReturnTo::RecentBooks:
+      goToRecentBooks(hint.selectIndex);
+      break;
+    case ReturnTo::GlobalBookmarks:
+      goToGlobalBookmarks(std::move(hint));
+      break;
+    case ReturnTo::Home:
+    default:
+      goHome(std::move(hint.selectName), hint.selectIndex);
+      break;
+  }
 }
 
 void ActivityManager::goToSleep() {
@@ -266,7 +345,10 @@ void ActivityManager::goToFullScreenMessage(std::string message, EpdFontFamily::
 
 void ActivityManager::goToWeather() { replaceActivity(std::make_unique<WeatherActivity>(renderer, mappedInput)); }
 
-void ActivityManager::goHome() { replaceActivity(std::make_unique<HomeActivity>(renderer, mappedInput)); }
+void ActivityManager::goHome(std::string focusBookPath, int focusSelectorIndex) {
+  hasReturnHint = false;
+  replaceActivity(std::make_unique<HomeActivity>(renderer, mappedInput, std::move(focusBookPath), focusSelectorIndex));
+}
 
 void ActivityManager::pushActivity(std::unique_ptr<Activity>&& activity) {
   if (pendingActivity) {
@@ -274,6 +356,10 @@ void ActivityManager::pushActivity(std::unique_ptr<Activity>&& activity) {
     LOG_ERR("ACT", "pendingActivity while pushActivity is not expected");
     pendingActivity.reset();
   }
+#if DEBUG_MEMORY_CONSUMPTION
+  LOG_DBG("ACT", "pushActivity requested: current=%s stackSize=%zu",
+          currentActivity ? currentActivity->getName().c_str() : "<none>", stackActivities.size());
+#endif
   pendingActivity = std::move(activity);
   pendingAction = PendingAction::Push;
 }

src/activities/ActivityManager.h

@@ -15,6 +15,23 @@
 class Activity;    // forward declaration
 class RenderLock;  // forward declaration
 
+// Where a "child" activity (launched via one of the replaceWith* helpers) should route
+// control when it exits successfully. See ActivityManager::returnFromChild().
+enum class ReturnTo : uint8_t { Home, FileBrowser, RecentBooks, GlobalBookmarks };
+
+// Minimal state the returning parent needs to restore its previous view (directory,
+// focused item, list index, or bookmark selection). Kept as a plain struct stored by
+// value on the ActivityManager — single instance, overwritten per transition, no heap
+// churn beyond the small strings.
+struct ReturnHint {
+  ReturnTo target = ReturnTo::Home;
+  std::string path;              // FileBrowser directory to restore
+  std::string selectName;        // item to re-focus in a list (file name, book title)
+  int selectIndex = -1;          // e.g. Recents index
+  std::string selectionContext;  // optional activity-specific restore key
+  int selectBookmarkIndex = -1;  // optional bookmark index for GlobalBookmarks
+};
+
 /**
  * ActivityManager
  *
@@ -68,6 +85,15 @@ class ActivityManager {
   // into the next one.
   bool drainInput = false;
 
+  // Where returnFromChild() should route to. Set by replaceWith*() helpers and
+  // preserved across plain goTo*() chains so a chained navigation flow can still
+  // restore its original parent state. Cleared only by returnFromChild() or by
+  // explicit goHome()/replaceWith*() calls, not by ordinary goTo*() transitions.
+  // Relevant symbols: ReturnHint, returnHint, hasReturnHint, returnFromChild(),
+  // goHome(), goTo*(), replaceWith*().
+  ReturnHint returnHint;
+  bool hasReturnHint = false;
+
  public:
   explicit ActivityManager(GfxRenderer& renderer, MappedInputManager& mappedInput)
       : renderer(renderer), mappedInput(mappedInput), renderingMutex(xSemaphoreCreateMutex()) {
@@ -85,18 +111,43 @@ class ActivityManager {
   // goTo... functions are convenient wrapper for replaceActivity()
   void goToFileTransfer();
   void goToSettings();
-  void goToFileBrowser(std::string path = {});
-  void goToRecentBooks();
+  void goToFileBrowser(std::string path = {}, std::string focusName = {});
+  void goToRecentBooks(int focusIndex = -1);
   void goToGlobalBookmarks();
+  void goToGlobalBookmarks(ReturnHint hint);
   void goToBrowser();
   void goToReader(std::string path);
   void goToKOReaderSync();
-  void pushReader(std::string path);
   void goToSleep();
   void goToBoot();
   void goToFullScreenMessage(std::string message, EpdFontFamily::Style style = EpdFontFamily::REGULAR);
   void goToWeather();
-  void goHome();
+  void goHome(std::string focusBookPath = {}, int focusSelectorIndex = -1);
+
+  // Replace-with-hint helpers: destroy the current activity before launching the new
+  // one (freeing its memory) and record where to route control when the new activity
+  // exits. Consumed by returnFromChild().
+  void replaceWithReader(std::string path, ReturnHint hint);
+  void replaceWithFileBrowser(std::string path, ReturnHint hint, std::string focusName = {});
+  void replaceWithRecentBooks(ReturnHint hint);
+
+  // Called by a "child" activity on successful exit. Consults the stored ReturnHint,
+  // clears it, and dispatches to the corresponding parent with restoration args. If
+  // no hint is set, defaults to goHome().
+  void returnFromChild();
+
+  // Record a ReturnHint before calling any plain goTo*() helper. Allows an activity
+  // (e.g. Home) to declare "when this flow ends, come back here with this state" for
+  // transitions where we don't want a dedicated replaceWith*() wrapper.
+  // Cleared by returnFromChild() or by an explicit goHome()/replaceWith*() call.
+  void setReturnHint(ReturnHint hint) {
+    returnHint = std::move(hint);
+    hasReturnHint = true;
+  }
+  void clearReturnHint() {
+    returnHint = {};
+    hasReturnHint = false;
+  }
 
   // This will move current activity to stack instead of deleting it
   void pushActivity(std::unique_ptr<Activity>&& activity);

src/activities/home/FileBrowserActivity.cpp

@@ -8,6 +8,7 @@
 
 #include <algorithm>
 
+#include "../ActivityManager.h"
 #include "../util/ConfirmationActivity.h"
 #include "BookInfoActivity.h"
 #include "CrossPointSettings.h"
@@ -113,6 +114,14 @@ void FileBrowserActivity::onEnter() {
   loadFiles();
   selectorIndex = 0;
 
+  if (!focusName.empty()) {
+    const size_t idx = findEntry(focusName);
+    if (idx < files.size()) {
+      selectorIndex = idx;
+    }
+    focusName.clear();
+  }
+
   requestUpdate();
 }
 
@@ -147,7 +156,8 @@ void FileBrowserActivity::loop() {
       loadFiles();
       const auto pos = oldPath.find_last_of('/');
       const std::string dirName = oldPath.substr(pos + 1) + "/";
-      selectorIndex = findEntry(dirName);
+      const size_t idx = findEntry(dirName);
+      selectorIndex = (idx < files.size()) ? idx : 0;
       requestUpdate();
     } else {
       onGoHome();
@@ -171,7 +181,12 @@ void FileBrowserActivity::loop() {
     } else {
       std::string fullPath = basepath;
       if (fullPath.back() != '/') fullPath += "/";
-      onSelectBook(fullPath + entry);
+      fullPath += entry;
+      ReturnHint hint;
+      hint.target = ReturnTo::FileBrowser;
+      hint.path = basepath;
+      hint.selectName = entry;
+      activityManager.replaceWithReader(std::move(fullPath), std::move(hint));
     }
     return;
   }
@@ -309,5 +324,5 @@ void FileBrowserActivity::render(RenderLock&&) {
 size_t FileBrowserActivity::findEntry(const std::string& name) const {
   for (size_t i = 0; i < files.size(); i++)
     if (files[i] == name) return i;
-  return 0;
+  return files.size();
 }

src/activities/home/FileBrowserActivity.h

@@ -19,6 +19,7 @@ class FileBrowserActivity final : public Activity {
 
   // Files state
   std::string basepath = "/";
+  std::string focusName;  // entry to select on first load (e.g. the file just returned from)
   std::vector<std::string> files;
 
   // Data loading
@@ -26,8 +27,11 @@ class FileBrowserActivity final : public Activity {
   size_t findEntry(const std::string& name) const;
 
  public:
-  explicit FileBrowserActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, std::string initialPath = "/")
-      : Activity("FileBrowser", renderer, mappedInput), basepath(initialPath.empty() ? "/" : std::move(initialPath)) {}
+  explicit FileBrowserActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, std::string initialPath = "/",
+                               std::string focusName = {})
+      : Activity("FileBrowser", renderer, mappedInput),
+        basepath(initialPath.empty() ? "/" : std::move(initialPath)),
+        focusName(std::move(focusName)) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/home/GlobalBookmarksActivity.cpp

@@ -9,6 +9,7 @@
 #include <algorithm>
 #include <cstdio>
 
+#include "../ActivityManager.h"
 #include "BookmarkStore.h"
 #include "CrossPointState.h"
 #include "GlobalBookmarkIndex.h"
@@ -26,6 +27,26 @@ void GlobalBookmarksActivity::onEnter() {
   const int first = firstSelectableIndex();
   selectorIndex = first >= 0 ? first : 0;
 
+  if (restoreHint.target == ReturnTo::GlobalBookmarks) {
+    const auto& entries = GLOBAL_BOOKMARKS.getEntries();
+    if (!restoreHint.selectionContext.empty() && restoreHint.selectBookmarkIndex >= 0) {
+      for (size_t i = 0; i < rows.size(); ++i) {
+        const auto& row = rows[i];
+        if (row.isSeparator) continue;
+        if (row.bookmarkIndex == static_cast<size_t>(restoreHint.selectBookmarkIndex) &&
+            row.bookIndex < entries.size() && entries[row.bookIndex].sourcePath == restoreHint.selectionContext) {
+          selectorIndex = static_cast<int>(i);
+          break;
+        }
+      }
+    }
+    if (selectorIndex < 0 || selectorIndex >= static_cast<int>(rows.size()) || isSeparatorRow(selectorIndex)) {
+      const int fallback = firstSelectableIndex();
+      selectorIndex = fallback >= 0 ? fallback : 0;
+    }
+    restoreHint = {};
+  }
+
   const auto total = static_cast<int>(rows.size());
   buttonNavigator.setSelectablePredicate([this](int index) { return !isSeparatorRow(index); }, total);
 
@@ -124,7 +145,11 @@ void GlobalBookmarksActivity::openSelected() {
   APP_STATE.saveToFile();
 
   LOG_DBG("GBA", "Jumping to bookmark in %s at %u/%u", entry.sourcePath.c_str(), bm.spineIndex, bm.pageNumber);
-  onSelectBook(entry.sourcePath);
+  ReturnHint hint;
+  hint.target = ReturnTo::GlobalBookmarks;
+  hint.selectionContext = entry.sourcePath;
+  hint.selectBookmarkIndex = static_cast<int>(row.bookmarkIndex);
+  activityManager.replaceWithReader(entry.sourcePath, std::move(hint));
 }
 
 template <typename Op>

src/activities/home/GlobalBookmarksActivity.h

@@ -20,8 +20,8 @@ struct Rect;
 // header separator or a bookmark entry belonging to the preceding header.
 class GlobalBookmarksActivity final : public Activity {
  public:
-  explicit GlobalBookmarksActivity(GfxRenderer& renderer, MappedInputManager& mappedInput)
-      : Activity("GlobalBookmarks", renderer, mappedInput) {}
+  explicit GlobalBookmarksActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, ReturnHint restoreHint = {})
+      : Activity("GlobalBookmarks", renderer, mappedInput), restoreHint(std::move(restoreHint)) {}
 
   void onEnter() override;
   void onExit() override;
@@ -38,6 +38,7 @@ class GlobalBookmarksActivity final : public Activity {
   ButtonNavigator buttonNavigator;
   std::vector<Row> rows;
   int selectorIndex = 0;
+  ReturnHint restoreHint;
 
   void rebuildRows();
   std::string getRowTitle(int index) const;

src/activities/home/HomeActivity.cpp

@@ -9,6 +9,7 @@
 #include <Utf8.h>
 #include <Xtc.h>
 
+#include <algorithm>
 #include <cstring>
 #include <vector>
 
@@ -211,6 +212,28 @@ void HomeActivity::onEnter() {
     recentsLoaded = true;
   }
 
+  // Apply focus: book path takes priority, else combined selector index (covers
+  // "return to the menu entry I was on").
+  bool focused = false;
+  if (!focusBookPath.empty()) {
+    for (size_t i = 0; i < recentBooks.size(); ++i) {
+      if (recentBooks[i].path == focusBookPath) {
+        selectorIndex = static_cast<int>(i);
+        focused = true;
+        break;
+      }
+    }
+    focusBookPath.clear();
+  }
+  if (!focused && focusSelectorIndex >= 0) {
+    rebuildMenuEntries();  // need menu count to clamp; rebuild is idempotent
+    const int combinedSize = static_cast<int>(recentBooks.size() + menuEntries.size());
+    if (combinedSize > 0) {
+      selectorIndex = std::min(focusSelectorIndex, combinedSize - 1);
+    }
+  }
+  focusSelectorIndex = -1;
+
   // Trigger first update
   menuEntriesDirty = true;
   requestUpdate();
@@ -348,9 +371,21 @@ void HomeActivity::render(RenderLock&&) {
   }
 }
 
-void HomeActivity::onSelectBook(const std::string& path) { activityManager.pushReader(path); }
+void HomeActivity::onSelectBook(const std::string& path) {
+  ReturnHint hint;
+  hint.target = ReturnTo::Home;
+  hint.selectName = path;  // used to re-focus the book in the recents strip after return
+  activityManager.replaceWithReader(path, std::move(hint));
+}
 
 void HomeActivity::dispatchMenuAction(MenuAction action) {
+  // Record where the menu entry was focused so that when the launched activity exits
+  // (via returnFromChild() or an empty-stack finish()), we come back to the same row.
+  ReturnHint hint;
+  hint.target = ReturnTo::Home;
+  hint.selectIndex = selectorIndex;
+  activityManager.setReturnHint(std::move(hint));
+
   switch (action) {
     case MenuAction::FileBrowser:
       activityManager.goToFileBrowser();

src/activities/home/HomeActivity.h

@@ -44,6 +44,9 @@ class HomeActivity final : public Activity {
   std::vector<MenuEntry> menuEntries;
   bool menuEntriesDirty = true;
 
+  std::string focusBookPath;    // book path to re-select on first render, if present in recents
+  int focusSelectorIndex = -1;  // fallback combined-selector index when focusBookPath doesn't match
+
   void onSelectBook(const std::string& path);
   void dispatchMenuAction(MenuAction action);
 
@@ -55,8 +58,11 @@ class HomeActivity final : public Activity {
   void loadRecentCovers(int coverHeight);
 
  public:
-  explicit HomeActivity(GfxRenderer& renderer, MappedInputManager& mappedInput)
-      : Activity("Home", renderer, mappedInput) {}
+  explicit HomeActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, std::string focusBookPath = {},
+                        int focusSelectorIndex = -1)
+      : Activity("Home", renderer, mappedInput),
+        focusBookPath(std::move(focusBookPath)),
+        focusSelectorIndex(focusSelectorIndex) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/home/RecentBooksActivity.cpp

@@ -7,6 +7,7 @@
 
 #include <algorithm>
 
+#include "../ActivityManager.h"
 #include "../util/ConfirmationActivity.h"
 #include "BookInfoActivity.h"
 #include "MappedInputManager.h"
@@ -35,6 +36,10 @@ void RecentBooksActivity::onEnter() {
   loadRecentBooks();
 
   selectorIndex = 0;
+  if (initialFocusIndex >= 0 && static_cast<size_t>(initialFocusIndex) < recentBooks.size()) {
+    selectorIndex = static_cast<size_t>(initialFocusIndex);
+  }
+  initialFocusIndex = -1;
   requestUpdate();
 }
 
@@ -49,7 +54,10 @@ void RecentBooksActivity::loop() {
   if (mappedInput.wasReleased(MappedInputManager::Button::Confirm) && !recentBooks.empty() &&
       selectorIndex < static_cast<int>(recentBooks.size())) {
     LOG_DBG("RBA", "Selected recent book: %s", recentBooks[selectorIndex].path.c_str());
-    onSelectBook(recentBooks[selectorIndex].path);
+    ReturnHint hint;
+    hint.target = ReturnTo::RecentBooks;
+    hint.selectIndex = static_cast<int>(selectorIndex);
+    activityManager.replaceWithReader(recentBooks[selectorIndex].path, std::move(hint));
     return;
   }
 

src/activities/home/RecentBooksActivity.h

@@ -14,6 +14,7 @@ class RecentBooksActivity final : public Activity {
   ButtonNavigator buttonNavigator;
 
   size_t selectorIndex = 0;
+  int initialFocusIndex = -1;  // applied once in onEnter(), then cleared
 
   // Recent tab state
   std::vector<RecentBook> recentBooks;
@@ -22,8 +23,8 @@ class RecentBooksActivity final : public Activity {
   void loadRecentBooks();
 
  public:
-  explicit RecentBooksActivity(GfxRenderer& renderer, MappedInputManager& mappedInput)
-      : Activity("RecentBooks", renderer, mappedInput) {}
+  explicit RecentBooksActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, int focusIndex = -1)
+      : Activity("RecentBooks", renderer, mappedInput), initialFocusIndex(focusIndex) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/reader/EpubReaderActivity.cpp

@@ -1,3 +1,7 @@
+#ifndef DEBUG_MEMORY_CONSUMPTION
+#define DEBUG_MEMORY_CONSUMPTION 0
+#endif
+
 #include "EpubReaderActivity.h"
 
 #include <Epub/Page.h>
@@ -35,11 +39,15 @@ constexpr unsigned long skipChapterMs = 700;
 // pages per minute, first item is 1 to prevent division by zero if accessed
 constexpr int PAGE_TURN_LABELS[] = {1, 1, 3, 6, 12};
 
+#if DEBUG_MEMORY_CONSUMPTION
 void logReaderMemSnapshot(const char* stage) {
   const uint32_t freeHeap = esp_get_free_heap_size();
   const uint32_t contigHeap = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT | MALLOC_CAP_DEFAULT);
   LOG_DBG("ERS", "Reader mem[%s]: free=%lu contig=%lu", stage, freeHeap, contigHeap);
 }
+#else
+inline void logReaderMemSnapshot(const char*) {}
+#endif
 
 bool writeReaderProgressCache(const std::string& cachePath, const int spineIndex, const int currentPage,
                               const int pageCount) {
@@ -91,10 +99,13 @@ void EpubReaderActivity::onEnter() {
     RenderLock lock(*this);
     ReaderUtils::applyOrientation(renderer, SETTINGS.orientation);
   }
+  logReaderMemSnapshot("onEnter_after_orientation");
 
   epub->setupCacheDir();
+  logReaderMemSnapshot("onEnter_after_setupCacheDir");
   applyPendingSyncSession();
   applyPendingBookmarkJump();
+  logReaderMemSnapshot("onEnter_after_pending_sync");
 
   FsFile f;
   if (Storage.openFileForRead("ERS", epub->getCachePath() + "/progress.bin", f)) {
@@ -120,9 +131,11 @@ void EpubReaderActivity::onEnter() {
       LOG_DBG("ERS", "Opened for first time, navigating to text reference at index %d", textSpineIndex);
     }
   }
+  logReaderMemSnapshot("onEnter_after_progress_load");
 
   // Load bookmarks for this book
   bookmarkStore.load(epub->getCachePath());
+  logReaderMemSnapshot("onEnter_after_bookmarks_loaded");
 
   // Save current epub as last opened epub and add to recent books
   APP_STATE.openEpubPath = epub->getPath();
@@ -135,8 +148,10 @@ void EpubReaderActivity::onEnter() {
   const RecentBook currentBook = RECENT_BOOKS.getBookByPath(epub->getPath());
   bookEmbeddedStyleOverride = currentBook.embeddedStyleOverride;
   bookImageRenderingOverride = currentBook.imageRenderingOverride;
+  logReaderMemSnapshot("onEnter_after_recent_books");
 
   // Trigger first update
+  logReaderMemSnapshot("onEnter_before_request_update");
   requestUpdate();
   logReaderMemSnapshot("onEnter_ready");
 }
@@ -1092,8 +1107,10 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
                                         const int orientedMarginRight, const int orientedMarginBottom,
                                         const int orientedMarginLeft) {
   const auto t0 = millis();
+  logReaderMemSnapshot("render_start");
   auto* fcm = renderer.getFontCacheManager();
   fcm->resetStats();
+  logReaderMemSnapshot("prewarm_begin");
 
   // Font prewarm: scan pass accumulates text, then prewarm, then real render
   const uint32_t heapBefore = esp_get_free_heap_size();
@@ -1106,14 +1123,17 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
 
   LOG_DBG("ERS", "Heap: before=%lu after=%lu delta=%ld", heapBefore, heapAfter,
           (int32_t)heapAfter - (int32_t)heapBefore);
+  logReaderMemSnapshot("prewarm_end");
 
   // Force special handling for pages with images when anti-aliasing is on
   bool imagePageWithAA = page->hasImages() && SETTINGS.textAntiAliasing;
 
+  logReaderMemSnapshot("before_bw_render");
   page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
   renderStatusBar();
   fcm->logStats("bw_render");
   const auto tBwRender = millis();
+  logReaderMemSnapshot("after_bw_render");
 
   if (imagePageWithAA) {
     // Double FAST_REFRESH with selective image blanking (pablohc's technique):
@@ -1140,34 +1160,44 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
   const auto tDisplay = millis();
 
   // Save bw buffer to reset buffer state after grayscale data sync
+  logReaderMemSnapshot("bw_store_begin");
   renderer.storeBwBuffer();
   const auto tBwStore = millis();
+  logReaderMemSnapshot("bw_store_end");
 
   // grayscale rendering
   // TODO: Only do this if font supports it
   if (SETTINGS.textAntiAliasing) {
+    logReaderMemSnapshot("gray_lsb_begin");
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
     page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
     renderer.copyGrayscaleLsbBuffers();
     const auto tGrayLsb = millis();
+    logReaderMemSnapshot("gray_lsb_end");
 
     // Render and copy to MSB buffer
+    logReaderMemSnapshot("gray_msb_begin");
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_MSB);
     page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
     renderer.copyGrayscaleMsbBuffers();
     const auto tGrayMsb = millis();
+    logReaderMemSnapshot("gray_msb_end");
 
     // display grayscale part
+    logReaderMemSnapshot("gray_display_begin");
     renderer.displayGrayBuffer();
     const auto tGrayDisplay = millis();
     renderer.setRenderMode(GfxRenderer::BW);
     fcm->logStats("gray");
+    logReaderMemSnapshot("gray_display_end");
 
     // restore the bw data
+    logReaderMemSnapshot("bw_restore_begin");
     renderer.restoreBwBuffer();
     const auto tBwRestore = millis();
+    logReaderMemSnapshot("bw_restore_end");
 
     const auto tEnd = millis();
     LOG_DBG("ERS",
@@ -1177,8 +1207,10 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
             tGrayMsb - tGrayLsb, tGrayDisplay - tGrayMsb, tBwRestore - tGrayDisplay, tEnd - t0);
   } else {
     // restore the bw data
+    logReaderMemSnapshot("bw_restore_begin");
     renderer.restoreBwBuffer();
     const auto tBwRestore = millis();
+    logReaderMemSnapshot("bw_restore_end");
 
     const auto tEnd = millis();
     LOG_DBG("ERS",

src/activities/reader/ReaderActivity.cpp

@@ -20,12 +20,20 @@
 #include "components/UITheme.h"
 #include "fontIds.h"
 
+#ifndef DEBUG_MEMORY_CONSUMPTION
+#define DEBUG_MEMORY_CONSUMPTION 0
+#endif
+
 namespace {
+#if DEBUG_MEMORY_CONSUMPTION
 void logReaderLaunchMemSnapshot(const char* stage) {
   const uint32_t freeHeap = esp_get_free_heap_size();
   const uint32_t contigHeap = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT | MALLOC_CAP_DEFAULT);
   LOG_DBG("READER", "Reader mem[%s]: free=%lu contig=%lu", stage, freeHeap, contigHeap);
 }
+#else
+inline void logReaderLaunchMemSnapshot(const char*) {}
+#endif
 }  // namespace
 
 std::string ReaderActivity::extractFolderPath(const std::string& filePath) {
@@ -102,28 +110,24 @@ void ReaderActivity::goToLibrary(const std::string& fromBookPath) {
 void ReaderActivity::onGoToEpubReader(std::unique_ptr<Epub> epub) {
   const auto epubPath = epub->getPath();
   currentBookPath = epubPath;
-  logReaderLaunchMemSnapshot("before_push_epub_reader");
-  startActivityForResult(std::make_unique<EpubReaderActivity>(renderer, mappedInput, std::move(epub)),
-                         [this](const ActivityResult&) { finish(); });
+  logReaderLaunchMemSnapshot("before_replace_epub_reader");
+  activityManager.replaceActivity(std::make_unique<EpubReaderActivity>(renderer, mappedInput, std::move(epub)));
 }
 
 void ReaderActivity::onGoToBmpViewer(const std::string& path) {
-  startActivityForResult(std::make_unique<BmpViewerActivity>(renderer, mappedInput, path),
-                         [this](const ActivityResult&) { finish(); });
+  activityManager.replaceActivity(std::make_unique<BmpViewerActivity>(renderer, mappedInput, path));
 }
 
 void ReaderActivity::onGoToXtcReader(std::unique_ptr<Xtc> xtc) {
   const auto xtcPath = xtc->getPath();
   currentBookPath = xtcPath;
-  startActivityForResult(std::make_unique<XtcReaderActivity>(renderer, mappedInput, std::move(xtc)),
-                         [this](const ActivityResult&) { finish(); });
+  activityManager.replaceActivity(std::make_unique<XtcReaderActivity>(renderer, mappedInput, std::move(xtc)));
 }
 
 void ReaderActivity::onGoToTxtReader(std::unique_ptr<Txt> txt) {
   const auto txtPath = txt->getPath();
   currentBookPath = txtPath;
-  startActivityForResult(std::make_unique<TxtReaderActivity>(renderer, mappedInput, std::move(txt)),
-                         [this](const ActivityResult&) { finish(); });
+  activityManager.replaceActivity(std::make_unique<TxtReaderActivity>(renderer, mappedInput, std::move(txt)));
 }
 
 void ReaderActivity::onEnter() {

src/activities/settings/KOReaderSettingsActivity.cpp

@@ -24,13 +24,14 @@ void KOReaderSettingsActivity::buildMenuItems() {
   menuItems.push_back(SettingInfo::Action(StrId::STR_PASSWORD, SettingAction::None));
 
   // Document matching: DynamicEnum toggling between Filename and Binary
-  menuItems.push_back(SettingInfo::DynamicEnum(
-      StrId::STR_DOCUMENT_MATCHING, {StrId::STR_FILENAME, StrId::STR_BINARY},
-      static_cast<SettingInfo::ValueGetterFn>([](const void*) -> uint8_t { return static_cast<uint8_t>(KOREADER_STORE.getMatchMethod()); }),
-      [](void*, uint8_t v) {
-        KOREADER_STORE.setMatchMethod(static_cast<DocumentMatchMethod>(v));
-        KOREADER_STORE.saveToFile();
-      }));
+  menuItems.push_back(SettingInfo::DynamicEnum(StrId::STR_DOCUMENT_MATCHING, {StrId::STR_FILENAME, StrId::STR_BINARY},
+                                               static_cast<SettingInfo::ValueGetterFn>([](const void*) -> uint8_t {
+                                                 return static_cast<uint8_t>(KOREADER_STORE.getMatchMethod());
+                                               }),
+                                               [](void*, uint8_t v) {
+                                                 KOREADER_STORE.setMatchMethod(static_cast<DocumentMatchMethod>(v));
+                                                 KOREADER_STORE.saveToFile();
+                                               }));
 
   // Authenticate and Register: ACTION items
   menuItems.push_back(