I've had a couple times where all the nodes in my workspace are outside the visible window so it's just a blank background and it's nearly impossible to get back to the nodes. One way this happens is when you copy a node from one workflow to another, that pasted node gets put "somewhere" outside the window so you have to hunt for it and then drag and drop it closer to the other nodes.
Work around: You can search for a node you know is in that workflow, but this doesn't solve getting the newly pasted node moved near your other nodes. It only gets you back after you've given up.
It would be greatly helpful to have a button that re-centers you on your nodes.