Hello!
As planed I’ve been working on ToolBox(es) and drop down menu for buttons. More extensive work on the visual appareance will be required thought. I think will now work on Gallery, and then polish everything.
A screen shot can be seen below:
Laurent Debacker.
Laurent Debacker 
Hi Laurent,
just a little idea – w/o having seen the code, the current state, and having any serious knowledge about UI architecture design:
Add another – optional – layer to support the native binding of Command pattern (see GangOfFour) style objects. A command object furthermore has the knowledge if it possibly activated and so on.
Why the idea: I just was working on my thesis and thought of a general example for the Command pattern.
-Thomas