This may be a minor or non-existent concern - maybe just something I've thought about a little too much.

As of r3945, the implementation of the touch screen appears to be that no action is taken until a touch is lifted.  This is undoubtedly how it must be if gestures can be implemented at all.  The exception to this appears to be that focus is moved within menus on touch 'down'.  Again, this is how it has to be, or else it would take two full touches within a menu to select anything - one to change the selection, then one to move right.

So what happens when you execute a gesture from within a menu is that focus often moves to a new item, then the gesture is recognized and executed.  What happens later, though, is that when you return to the menu Fab4 remembers the newly selected menu position.  That could be inconvenient for someone, particularly when using the device as a controller and moving in and out of the same menus.

What I'm suggesting is that when a gesture is executed from within a menu, throw away any new menu item selection that happened at the beginning of the gesture and remember the old selection.