How does IDEA know when and how to undo an action?
Apparently changing a file as part of an action through the VFS does not add
the action in the undo list. How do I create an action that can be undone? I
believe there is no way to get notification that an action was undone so how
does IDEA undo the side effects? Through the LVCS? Anyhow it would be
useful to have a callback on AnAction to get notified when an action is
undone. This would be required to keep external resources in sync.