Once a tool is 'Torn Off' and collapsed, I would find it very much more convenient if one of its icons were to remain (more) visible. At the moment you have to roll the mouse over the tool to get it to expand, to be sure you're on the right one.
Either that or make them semi-transparent and have them only become live/selectable at the 'blue-bar' end of the tool to allow you to draw through them.


Thanks.
Martin.