protected override void OnGetPreferredHeightForWidth(int width, out int minimum_height, out int natural_height)
{
int min1, height1, min2, height2, sw = Handler.SplitterWidth;
Child1.GetPreferredHeightForWidth(width, out min1, out height1);
Child2.GetPreferredHeightForWidth(width, out min2, out height2);
minimum_height = Handler.GetPreferredPanelSize(min1, min2);
natural_height = Handler.GetPreferredPanelSize(height1, height2);
}