message: Remove unnecessary isEmpty() check
  The mHighlightIndex bounds check will correctly handle the empty case.
diff: @@ -176,8 +176,7 @@ void ListBox::onMouseDown(EventHandler::MouseButton /*button*/, int x, int y)
  void ListBox::onMouseMove(int x, int y, int /*relX*/, int /*relY*/)
  {
  - // Ignore if menu is empty or invisible
  - if (isEmpty() || !visible()) { return; }
  + if (!visible()) { return; }
  if (!mScrollArea.contains({x, y}))
  {
  