Comment 10 for bug 575978

Created attachment 60809
Change-degree-and-diaeresis-keys-to-deadkeys.patch

Forwarding this (stalled) bug from Ubuntu:
  https://bugs.launchpad.net/ubuntu/+source/xkeyboard-config/+bug/575978

[Original Report]
The Icelandic keyboard layout currently has a key with a degree sign (°) and an umlaut/diaeresis sign (¨). The normal function of this key appears to be to compose with the next character to form "å" or "ä", but in Ubuntu (up to and including 10.04 - Lucid Lynx) the key produces the abovementioned signs by themselves.

Line 26 in "/usr/share/X11/xkb/symbols/is" reads

key <TLDE> { [ degree, diaeresis, notsign, notsign ] };

Changing this to

key <TLDE> { [ dead_abovering, dead_diaeresis, notsign, notsign ] };

Appears to fix the problem.

Reasonable image of an Icelandic keyboard is:
http://commons.wikimedia.org/wiki/File:KB_Iceland.svg

[Discussion]
The main question is: Do either of these key symbols have separate use in Icelandic? Perhaps as a degree symbol for temperatures, but that's hardly unique to Icelandic, and other keyboards don't have such a key for that symbol (at least, standard US keyboards don't).

I found a virtual keyboard at http://mylanguages.org/icelandic_keyboard.php, where this key does in fact work as a deadkey for producing åůäüïöëÿ. (other letters result in just the ° or ¨ printed).