ctrl + z

[heaven692]

Pov : You have been working on a composition for more than 4 hours and you accidentally press ctrl + z thanks adobe to add this shortcut 👍

[Seth Murphy Creative · Accepted solution]

Solution: Edit > Undo (Action). Ctrl+Shift+Z should also do the trick. 

This is a short a simple way to use a very useful tool, and undo the wrongful use of said tool.