This happens to me a lot:
I write some algorithm to process a data input. It works, but there's one value of the input that needs a different algorithm. So I draw a Case Structure around my existing code. My data input is now one of the tunnels into the structure. I delete the tunnel, wire the outside broken wire to the case selector "?" terminal and wire the inside of the ? terminal to the inside broken wire. Then I move the ? terminal to the same location where the tunnel used to be.
It's annoying and entirely mechanical. I propose we add a pop up item that allows an existing input tunnel to be quickly converted into the case selector. If the tunnel is on the top or the bottom (or, heaven forbid, the right edge) of the structure then it gets moved to the left edge, but if the tunnel is already on the left edge then the ? terminal moves to that location. If the ? was already wired, the existing connections would be replaced with a regular tunnel.
