XKB plugin forget settings for default layout, keyboard shortcut for changing layout and keyboard model even without reboot.
I think the explanation given here [1] explains this issue: the Xfce keyboard layout manager overrides the plugin. Also note that since commit fb667951f66a05b87949b3eaf9e7c04697899fea (which fixed Bug 5476 and is not 0.5.4.3) the plugin does not persist the layouts -- this is left to Xfce, which in turn can leave it to X (if "Use system defaults" is checked). So, try running the current master: in the most recent version, the settings are no longer modified through the plugin. [1] https://bugs.launchpad.net/ubuntu/+source/xfce4-xkb-plugin/+bug/944468/comments/13
Assuming you're running xfce 4.8 or 4.10, this should be fixed in xkb-plugin 0.5.5 *** This bug has been marked as a duplicate of bug 5637 ***