It is not possible to assign a shortcut with "Mod4" in the keyboard settings. If you try to assign "Ctrl+Alt+Mod4+e" for example, you only get "Crtl+Alt+e". In the Windows Manager keyboard settings dialog it works as expected. But you can edit your keyboard settings manually ("~/.config/xfce4/shortcuts/my.xml" for example) you can add a "+Mod4", then reload the keyboard configuration and it works as expected.
Sounds like a Gtk/Gdk bug to me. Which version of gtk do you have ?
x11-libs/gtk+ 2.8.19
you should try upgrading gtk+ to version 2.10.x
i have upgraded gtk to 2.10.1. the keyboard assignment works as expected: now using "Super" instead of "Mod4". thanks for your help.
i close the bug then
*** Bug 2204 has been marked as a duplicate of this bug. ***
*** Bug 2215 has been marked as a duplicate of this bug. ***
*** Bug 2324 has been marked as a duplicate of this bug. ***
*** Bug 2366 has been marked as a duplicate of this bug. ***