It's impossible for an X app to draw on top of the Unity shell because the Unity shell is part of Compiz and designed to always draw after app windows (hence appears on top).
If you want the appearance of Unity not being on top then you need to modify the Unity code so that it doesn't draw itself on top, or not draw itself at all under certain conditions.
It's impossible for an X app to draw on top of the Unity shell because the Unity shell is part of Compiz and designed to always draw after app windows (hence appears on top).
If you want the appearance of Unity not being on top then you need to modify the Unity code so that it doesn't draw itself on top, or not draw itself at all under certain conditions.