On that matter, i have STR on a xinerama setup. have the window on top of fullscreen app, alt-tab to the fullscreen app -> the window disappears. Alt-tab to the hidden window -> doesnt come up. Focus other window on other screen with mouse, focus back the fullscreen window, focus back 'other window on other screen' - the previously hidden windowed app comes on top of fullscreen app, unfocused.
On that matter, i have STR on a xinerama setup. have the window on top of fullscreen app, alt-tab to the fullscreen app -> the window disappears. Alt-tab to the hidden window -> doesnt come up. Focus other window on other screen with mouse, focus back the fullscreen window, focus back 'other window on other screen' - the previously hidden windowed app comes on top of fullscreen app, unfocused.