Normally when you put your mouse over an item in the model tree there is a red box to show you what you are hovering over. It would be nice if this option is extended for when the constraint menu is up.
It currently will show the plane in the model that you are hovering over, but it doesn't show the red box. If you are working in a geometrically large assembly that plane might be off the view of the screen, so to make sure I am selecting the right one that red box would be helpful.
Attached is a screenshot of the little red box.