Solved (for anyone else owner-drawing controls):
protected override void WndProc(ref Message m)
{
const int WM_WINDOWPOSCHANGED = 0x0047;
base.WndProc(ref m);
if (m.Msg == WM_WINDOWPOSCHANGED)
{
//Make changes to your display rectangle here...
this.PerformLayout();
}
}
solved Winforms owner-drawn controls and resizing