SDL no longer grabs the keyboard by default on X11.

You can re-enable that functionality by setting a new hint SDL_HINT_GRAB_KEYBOARD

include/SDL_hints.h

@@ -152,6 +152,17 @@ extern "C" {
  */
 #define SDL_HINT_VIDEO_X11_XRANDR           "SDL_VIDEO_X11_XRANDR"
 
+/**
+ *  \brief  A variable controlling whether grabbing input grabs the keyboard
+ *
+ *  This variable can be set to the following values:
+ *    "0"       - Grab will affect only the mouse
+ *    "1"       - Grab will affect mouse and keyboard
+ *
+ *  By default SDL will not grab the keyboard so system shortcuts still work.
+ */
+#define SDL_HINT_GRAB_KEYBOARD              "SDL_GRAB_KEYBOARD"
+
 /**
  *  \brief  A variable controlling whether the idle timer is disabled on iOS.
  *