Is there anyway you can pick which operation you wish to redo, or are you just able to undo the last change in sequence?  There are times I have added FX to a recorded track and want to go back and keep the effects but just redo the track.  I know I can go to "wipe" and just wipe and redo the track, but what if you just want to undo a clip or edit?  It would be nice to go to a menu of your actions and just "undo" that particular item.  

Undo is implemented as a FILO (first-in-last-out) stack, meaning you have to undo in reverse sequential order. It's designed that way because only adjacent actions can be guaranteed to be un-doable.

PS you might want to try not applying EFX to a track as that is called "destructive" ( undo-able)  editing. 
Most users always put the effects in a effect bin for the track, or in a effects send from the track to a effect bus. 
This way you do have the options to return to a different scenario. 

Gottcha.  That's what I thought, it's all making sense now.  Thanks.