Ah - understand the problem, after looking up Swedish keyboard layout
. The default function of the AltGr key in Gnome is to function as a "compose" key, allowing the entry of accented characters. However, it should be possible to switch the function to a different key
System > Preferences > Keyboard > Layouts > Layout options> Compose key position
Testing this on my laptop, it isn't working for me at the moment (a restart of Gnome may be required).
Hope this helps a little,