I noticed today that if I select a prefab in the project pane, then tap on the empty area of the inspector pane, a script from my project is inserted into the prefab.
I have been seeing uninvited scripts in prefabs quite a bit, and I think this is where they come from. What is “H” supposed to be doing, and more importantly, can I turn it off somehow? I’ve made some terrible messes with this thing and my fat fingers.
Could someone give this a try and see if it happens to them? Maybe I’ve broken my editor somehow.
No, this doesn’t happen to me. What script is being added, just a random one?
“H” does nothing for me.
Do you get this behavior in every Unity project?
H only does something for me if I have an item whose name begins with H. Then that item is selected.
I remember that in a previous version if a script had an underscore in the name, the letter after the underscore became a shortcut for adding that script. This has been fixed though, as far as I remember…
Was bugging me for a while because I had lots of scripts called GUI_this and GUI_that and weird stuff kept happening…
Check under Component > Scripts if any scripts have a shortcut assigned (shows as a letter on the right side of the menu)…
AHA! They DO have shortcut keys assigned. Looks like it’s scripts with underscores in them as well, so I guess this has not been fixed.
I have a lot of scripts with underscores in the file names, class names and references … and I’m on a short deadline now, so I guess I just have to live with it for this project. 
Thanks for clearing that up.