"Cannot call this method on an empty rect" when holding backspace to delete formula characters on a slower machine

Reproduces reliably in PopupListWatcher for me when I am using a slower virtual machine and quickly delete formula symbols up until the opening bracket disappears (`=FUNCTION("blah-blah"` =>>> `=FUNCTION`)

It seems harmless otherwise, does not crash the app (probably due to a try/catch up the stack), but I wonder if it should be handled more gracefully.