In the "Add/Edit a Command" window, if a textbox(E.G. "When I say" or "Category") has focus, using the "Undo" key combination Ctrl-Z will affect both the textbox and the action list; The action list will also steal focus when this occurs.
Ctrl-Y behavior is also somewhat strange, in that it will equally affect and give the action list focus, but has no effect on the textbox(Perhaps the undo/redo list is wiped when focus switches away from the textbox?).
EDIT: Fully fixed in v1.6.8