An scipted macro to Undo selection.
What is it good for ?
during Animating proccess (or navigating objects), user need to swich between controllers or objects for many times. every time they need to navigate viewport and select new controllers. in the case of normal undo of max, your actions will be undo too. this Script is for Undo only the selection sets and keep actions.
note: this Script only works in object-mode selections and not any sub-level selections like vertex and edjes.
After placing files , Run Max, go to Customize > Customize user interface > toolbars tab