AdvStringGrid display some kind of shadow while displaying a custom editor

I got some kind of bad rendering while displaying a custom editor using a formcontrolEditLink. It is difficule to explain thats why I join a animated gif to see the problem.
My formcontroledit is a panel. Any idee how to remove this shadow ? Thanks

Are you using the FocusHelper component on this form?
If so, I suspect that must be causing this. To verify, can you see if disabling it makes a difference?

I have disabled the focusHelper and now it works as expected. Thank you for your help.