The Lighting Controller

If you double click in the - actually I'll take a screen shot.

If you double click anywhere in the blue area then Builder has and error and closes or if you run your mouse over the red area builder has to close.

What a strange idea to click in this area, while no group has been created there before
Anyway, you're right Tom !

Added in the TODO list.

I know! I found it because I passed my mouse over the red area then decided to look in to the problem more deeply and discovered that clicking in this area also causes the problem