Undo (ctrl-z) does nothing while using Fill & Sign.

Add a text box, fill in text, then click outside it. Nothing happens I assume. I did this 3-4 times, then clicked on signature to add that. Signature image was added, but then it lost focus. I guessed it might have gone behind the form itself. So I try to ctrl-z to undo my last actions (standard ctrl shortcut on Windows for undo). Nothing happens.

And I don't see a menu option for undo either. Every action will be manual during Fill & Sign? Why even claim it helps anything? I was expecting OCR and it to create text fields automatically in blank space on this obvious form (Oregon Department of Revenue tax form). Not this add a text field, type a bit, then adjust where it truly appears (repeat ad infinitum)