[Chimera-users] Is it possible to undo an action?

[Lesheng Kong]

Hi,
Is it possible to undo an action in Chimera?
I notice that some actions in Chimera can be undid, such as "undo 
selection" or "undo move". Can every action be undid in Chimera?
For example, I colored a selection zone in a different color. But I 
want to undo this action and recover each atom's previous color.
Thank you very much!
With best regards,
Lesheng