title: can not delete the node in the work-flow when the work flow is offline
body: <p>when the work-flow is offline, I'm not able to operator the specified node.it does not give me any response when I click the right of the mouse.If it is normal,it will show the following response.<a href="https://i.stack.imgur.com/WHmCD.png" rel="nofollow noreferrer">enter image description here</a></p>