message: Remove shadow field `mHasFocus` from `ListBoxBase`
diff: @@ -103,8 +103,6 @@ private:
  int mItemHeight = 1; /**< Height of a ListBoxItem. */
  int mItemWidth = 0; /**< Width of a ListBoxItem. */
  - bool mHasFocus = false;
  -
  NAS2D::Color mText = NAS2D::Color::White; /**< Text Color */
  NAS2D::Color mHighlightBg = NAS2D::Color::DarkGreen; /**< Highlight Background color. */
  NAS2D::Color mHighlightText = NAS2D::Color::White; /**< Text Color for an item that is currently highlighted. */
  