[moved from: https://bugs.launchpad.net/ubuntu/+source/xkeyboard-config/+bug/577532]


Seems that, although mapped correctly, the Super key does not work as a modifier key in keyboard shortcuts for Gnome/Gtk apps.

Very detailed description here: https://answers.launchpad.net/ubuntu/+question/110098

Steps to test
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1) Open gedit
2) Go to Edit > Preferences > Plugins and enable the Snippets plugin
3) Click 'Configure Plugin'
4) In the Snippets manager, create a new snippet under 'Global'.
    Enter your name in the 'Edit' box.
    In 'Tab trigger' field, type the letter n.
    Click the Shortcut key field, and then hold down the Super (Win) key and n. Shortcut assigned should read 'Super+N'.
    Close the Snippets manager and the Preferences dialog.
5) Create a new document. In the editor, type the letter n and hit the tab key. You should see your name appear. That means the snippets are working.
6) In the editor, hold the Super key and then hit the n key. You should simply see the letter n.

Additional details
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Have tested this on both Kubuntu 10.04 and UNR 10.04. On both machines, the shortcut keys above worked as expected in K/Ubuntu 9.10, but broke upon upgrade to 10.04 (one machine was upgraded, one fresh-installed).

Have also installed openSUSE via Virtualbox to test this, and it works as expected there, so I've got to assume it's an Ubuntu-specific problem. FWIW, the output of xmodmap and xev testing are basically identical across all three systems.