Rectangle Selection , The selected scan area is beyond the control's range of Helix Viewport3D Wpf

[MauNguyenVan]

RectangleSelection , The selected scan area is beyond the control's range of Helix Viewport3D Wpf, It takes over other control space. I have try HelixViewport3D.ClipToBounds = true. but it does not work.

How can I limit the rectangle elected scan inside HelixViewport3D control space. Thanks.