Why won't my xmodmap command run on startup/login?

~/.profile runs early in the login sequence. If your desktop environment configures a keyboard layout, it can overwrite the settings you've just loaded.

Put your settings in a file called ~/.Xmodmap:

keysym Delete = Menu
keysym Menu = Delete

Under the default Gnome environment in Ubuntu 10.04, the next time you log in, you will be prompted as to whether to load ~/.Xmodmap. Load it, and tick “don't ask me again”. Then your .Xmodmap will be applied after the default settings.

I found that in the place in Gconf-Editor mentioned above the name of your revised keyboard layout should appear twice, once under "known_file_list" and once under "update_handlers". As to why Ubuntu sometimes puts in the latter entry, and sometimes doesn't... well, it keeps you on your toes, doesn't it?

Incidentally, after a lot of research I used the above tweak to re-assign the Left Windows key. I put the following statement in my own keyboard layout to make it duplicate the Left Arrow key:-

keycode 133 = 0xFF51

(Check that those are the right codes for you by going into xev and pressing first one key then the other.)

It's only a little point, but while I'm on the Internet it gives me a convenient "Back" key - Alt+Win with the left hand. I can do it without looking.

Some systems look for a file named ~/.Xmodmap and execute the commands found there. Try putting these lines in that file:

keysym Delete = Menu
keysym Menu = Delete