A Copy action doesn't change the image so it should not be put on the undo stack. Right now it is, because of the code shared with the Cut action.
Git commit c55fc01853631061df04b05ff65fd0f315c2a0bf by Boudewijn Rempt.
Committed on 26/01/2015 at 14:01.
Pushed by rempt into branch 'calligra/2.9'.
Don't push Copy onto the undo stack
The copy action doesn't affect the document state, so doesn't need
to be undoable (and in fact, undoing a copy didn't undo the change
to the clipboard).
M +40 -38 krita/ui/actions/kis_selection_action_factories.cpp