message: Extract common constant for `NoSelection`
diff: @@ -16,6 +16,7 @@ namespace
  {
  constexpr int Width = 48;
  constexpr int Offset = constants::MarginTight + 32;
  + constexpr std::size_t NoSelection = SIZE_MAX;
  const std::map<NotificationArea::NotificationType, Rectangle<float>> NotificationIconRect
  @@ -64,7 +65,7 @@ const std::string& StringFromNotificationType(const NotificationArea::Notificati
  NotificationArea::NotificationArea() :
  mIcons{imageCache.load("ui/icons.png")},
  mFont{fontCache.load(constants::FONT_PRIMARY, constants::FontPrimaryNormal)},
  - mNotificationIndex{SIZE_MAX}
  + mNotificationIndex{NoSelection}
  {
  auto& eventhandler = Utility<EventHandler>::get();
  @@ -113,7 +114,7 @@ std::size_t NotificationArea::notificationIndex(NAS2D::Point<int> pixelPosition)
  return count;
  }
  }
  - return SIZE_MAX;
  + return NoSelection;
  }
  @@ -126,7 +127,7 @@ void NotificationArea::onMouseDown(EventHandler::MouseButton button, int x, int
  }
  const auto count = notificationIndex({x, y});
  - if (count != SIZE_MAX)
  + if (count != NoSelection)
  {
  if (button == EventHandler::MouseButton::Left)
  {
  @@ -144,7 +145,7 @@ void NotificationArea::onMouseMove(int x, int y, int /*dX*/, int /*dY*/)
  if (!rect().contains({x, y})) { return; }
  mNotificationIndex = notificationIndex({x, y});
  - if (mNotificationIndex != SIZE_MAX)
  + if (mNotificationIndex != NoSelection)
  {
  const auto& rect = notificationRect(mNotificationIndex);
  