gui freeze when sending too many fullscreen commands
to reproduce, hold f shortkey for a few seconds.
VLC is then locked on a mutex. Backtrace :
Thread 3 (Thread 0xb4c71b70 (LWP 3325)):
[#0](https://code.videolan.org/videolan/vlc/-/issues/0) 0x04de3dc1 in QMutex::lock() () from /home/qt/qt-4.7.4-install/lib/libQtCore.so.4
[#1](https://code.videolan.org/videolan/vlc/-/issues/1) 0x04eed254 in QCoreApplication::postEvent(QObject*, QEvent*, int) () from /home/qt/qt-4.7.4-install/lib/libQtCore.so.4
[#2](https://code.videolan.org/videolan/vlc/-/issues/2) 0x04eed5dc in QCoreApplication::postEvent(QObject*, QEvent*) () from /home/qt/qt-4.7.4-install/lib/libQtCore.so.4
[#3](https://code.videolan.org/videolan/vlc/-/issues/3) 0x0109a710 in FullscreenControllerWidget::fullscreenChanged (this=0x928e5e8, p_vout=0x9364a70, b_fs=false, i_timeout=1000)
at ../../../../modules/gui/qt4/components/controller.cpp:1175
[#4](https://code.videolan.org/videolan/vlc/-/issues/4) 0x0109a81a in FullscreenControllerWidgetFullscreenChanged (vlc_object=0x9364a70, variable=0x6a50d1 "fullscreen", old_val=...,
new_val=<value optimized out>, data=0x928e5e8) at ../../../../modules/gui/qt4/components/controller.cpp:1068
[#5](https://code.videolan.org/videolan/vlc/-/issues/5) 0x00678ca5 in TriggerCallback (p_this=0x9364a70, p_var=0x9585938, psz_name=0x6a50d1 "fullscreen", oldval=...) at ../../src/misc/variables.c:1367
[#6](https://code.videolan.org/videolan/vlc/-/issues/6) 0x006779a1 in var_SetChecked (p_this=0x9364a70, psz_name=0x6a50d1 "fullscreen", expected_type=32, val=...) at ../../src/misc/variables.c:766
[#7](https://code.videolan.org/videolan/vlc/-/issues/7) 0x0063cad7 in var_SetBool (p_obj=0x9364a70, psz_name=0x6a50d1 "fullscreen", b=false) at ../../include/vlc_variables.h:224
[#8](https://code.videolan.org/videolan/vlc/-/issues/8) 0x00640ac8 in ThreadChangeFullscreen (vout=0x9364a70, fullscreen=false) at ../../src/video_output/video_output.c:1272
[#9](https://code.videolan.org/videolan/vlc/-/issues/9) 0x006416eb in Thread (object=0x9364a70) at ../../src/video_output/video_output.c:1548
[#10](https://code.videolan.org/videolan/vlc/-/issues/10) 0x00efe96e in start_thread (arg=0xb4c71b70) at pthread_create.c:300
[#11](https://code.videolan.org/videolan/vlc/-/issues/11) 0x001e4a4e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130
I don't know if the bug is in video output or gui.