Comment # 1 on bug 937193 from Stefan Seyfried

There are lots of duplicate keyboard shortcuts in many languages in the setting
dialog, please raise this with XFCE upstream.
Alt-A takes you back to "A"ll settings.

It is possible to work around by navigating via TAB / cursor keys and
activating the option with enter.

I'll close this as wontfix, again, please raise this upstream.