So when you remove the shortcut at First Object Above, it still doesn't work at Add new index entry (reversed)?
That's strange.
I have figured it out (partialy). Changing entrie in in Show set was not useless, saving txt file for a new set was not succesfull (or I did not know how propery save it, of course at another set name and use it). At the end of all trials, I create a new set in menu Keyboard comand and just change the shortcut for the desired index. It works for the old file, the same idml file, old other files, but not for the new file.
Makes me crazy. I need that solution too.