We are seeing issue with <Tab> and p not working in XFCE 4.8.0 and 4.12.1 with OSX x2goclient 4.0.5.0. This appears to be due to the default mapping of <Super><Tab> and <Super>p to keyboard shortcuts by xfce and no <Super> key defined by XQuartz. XFCE bug is https://bugzilla.xfce.org/show_bug.cgi?id=10760
A workaround for the OSX client is to define the Super keys in ~/.Xmodmap:
keycode 63 = Super_L keycode 71 = Super_R
or similar.
-- Orion Poplawski Technical Manager 303-415-9701 x222 NWRA, Boulder/CoRA Office FAX: 303-415-9702 3380 Mitchell Lane orion@nwra.com Boulder, CO 80301 http://www.nwra.com