Your comments

This doesn't seem to be working in the latest .18 version. Last time I mentioned hotkeys there was some issues with them on PC. Is that still the case?
bah! It's working now just because you asked. I've had this behaviour at other times too. But then it was when I connected certain nodes. Sadly I've not been able to reproduce it in any consistent way.
Alt + RMB over connections crashes Shaderforge for me. The window freezes and looses a lot of nodes due to what I suppose is a graphical glitch. But the rest of unity runs fine.
Good to hear that it wasn't a hard to track down / obscure issue then!
Please do!
Not sure if our setup is an issue, but we are both on laptops with a secondary screen as the main one.
I just tried it on the coders computer (he's also on windows (x64)) and it's the same thing. Neither delete connection nor cut/copy/paste/duplicate works.
Yes I've tried restarting. The delete functionality has never worked here really. I've tried it a couple of times (whenever I remembered that the functionality should be there).
It could be something with my setup maybe?