ElementOperationException was found in using send hotkey

Hi Everyone

I tried to send hotkey to manupulate Google Chrome (Paste text into new mail box) , And then I found Error happend(ElementOperationException).

I have already checked Selecter property of send hotkey activity was blank and there’s no element designated.

I thought send hotkey activity just send key regardless of app or attachecd window, but is it correct?

Could I ask you what is the cause of this issue?