Review comments

src/activities/browser/OpdsBookBrowserActivity.cpp

@@ -209,10 +209,10 @@ void OpdsBookBrowserActivity::loop() {
       return;
     }
 
-    buttonNavigator.onNextList(formatSelectorIndex, static_cast<int>(entry.acquisitionLinks.size()),
-                               [this] { requestUpdate(); });
-    buttonNavigator.onPreviousList(formatSelectorIndex, static_cast<int>(entry.acquisitionLinks.size()),
-                                   [this] { requestUpdate(); });
+    buttonNavigator.onNextList({MappedInputManager::Button::Down}, formatSelectorIndex,
+                               static_cast<int>(entry.acquisitionLinks.size()), [this] { requestUpdate(); });
+    buttonNavigator.onPreviousList({MappedInputManager::Button::Up}, formatSelectorIndex,
+                                   static_cast<int>(entry.acquisitionLinks.size()), [this] { requestUpdate(); });
     return;
   }
 

src/util/ButtonNavigator.cpp

@@ -287,7 +287,8 @@ void ButtonNavigator::onListNav(const Buttons& buttons, const bool forward, int&
 
   if (isDouble) {
     // Restore to position before the first press so the total movement is exactly listJumpCount.
-    selectedIndex = indexBeforePress;
+    // Guard against a stale indexBeforePress if totalItems shrank since the single press stored it.
+    selectedIndex = (indexBeforePress >= 0 && indexBeforePress < totalItems) ? indexBeforePress : selectedIndex;
     for (int i = 0; i < listJumpCount; ++i) {
       const int next =
           forward ? (selectablePredicate ? nextIndex(selectedIndex) : nextIndex(selectedIndex, totalItems))