xfsettingsd swallows up wrong shortcuts

If there are more keyboard layouts defined, the detection of shortcuts in xfsettingsd swallows up wrong combinations.

Example:

• define two layouts, US+Hungarian (setxkbmap -model pc101 -layout 'us,hu'). In the Hungarian layout the Backslash is AltGr+Q
• define an xfce shortcut for Control-Backslash - it will work as expected.
• But Control-Q stops working in all applications and it does not trigger anything in XFCE either.

Distro: debian/testing. xfce4-settings 4.14.2-1

The same bug was discussed back in 2014 with interfering other layouts. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=741463#26