message: Remove conditional clear background to black
  Background will always be fully painted by following code. Following
  code is also safe, even when the ListBox is empty.
diff: @@ -245,12 +245,6 @@ void ListBox::update()
  const auto borderColor = hasFocus() ? mBorderColorActive : mBorderColorNormal;
  renderer.drawBox(mRect, borderColor);
  - if (empty())
  - {
  - renderer.drawBoxFilled(mRect.inset(1), NAS2D::Color::Black);
  - return;
  - }
  -
  renderer.clipRect(mRect);
  // draw boundaries of the widget
  