Elements don't clear focus after being removed from the screen

[MoffKalast]

A focused Button can be activated using the space bar after the container has been removed from the main lemur root node.

Notes:

• my setup uses the separate viewport method instead of rendering inside the guiNode
• the button is attached to a Container
• Container layout is set to SpringGrid with multiple rows of buttons

[pspeed42]

Just a note for myself... this is related to: https://github.com/jMonkeyEngine-Contributions/Lemur/issues/28

[pspeed42]

This should be fixed now and will show up in v 1.10