With the transition from xfwm4-4.11.1 to xfwm4-4.11.2, xfwm stopped showing windows under full-screen (default keyboard shortcut ALT+F11) windows under certain conditions. When starting an application, for example via keyboard shortcut, the behavior is normal and the new window is being brought to the top. However, when using the task switcher (e.g. ALT+TAB) for changing window focus, once the full-screen window has been focused, non-full-screened windows will never show up again when giving focus to them. Going back to 4.11.1 fixes this.
I confirm this behaviour. The change was caused by adding the call to clientSetFocus() on line 499 of src/cycle.c
From the output of g_message() on the previous line, c2 is always NULL. With this value clientSetFocus() removes focus, but when the current window is fullscreen the broken behaviour results.
Same Issue for me.
This has already been reported and is under investigation.
*** This bug has been marked as a duplicate of bug 11167 ***
*** Bug 11125 has been marked as a duplicate of this bug. ***