Are you just pressing Shift+Tab? Have you changed any defaults? Can you add details on specifically what you're doing and what your configuration is?
Also, what game are you running when you try to bring up the overlay?
My configuration is gnu/linux with a full state-of-art mesa opengl stack for
radeon GPUs. My radeon GPU is tahiti xt (R9 280X), I use the linux 4.1 with
all the fixes from AMD (agd5f). drm, llvm, mesa, xserver, ati xorg
driver, all from their git repos from last week-end.
I have a basic x11 window manager which does not support x11 hints for fullscreen
(it is a heavily modified old openbox).
I'm unable to make the web based overlay appear in any game I tried
(portal2/dota2/mark of the ninja...). I tried the default shift+tab, f12... My
x11 xkb configuration is in /share/x11, but their is a link in /usr/share/x11
pointing at /share/X11.
The bigpicture overlay is appearing in all the games I tried with the above key
shortcuts.
Sylvain
Nothing extracted yet.
I cannot get the web overlay to appear. The big picture
overlay does appear.
(mesa radeon drivers? keyboard xkb?...)