diff -r 9a65b2bd4e01 src/video/x11/SDL_x11window.c
--- a/src/video/x11/SDL_x11window.c	Mon Jun 04 12:31:14 2012 -0400
+++ b/src/video/x11/SDL_x11window.c	Tue Jun 12 14:42:31 2012 +0800
@@ -1019,12 +1019,18 @@
         /* Raise the window if we grab the mouse */
         XRaiseWindow(display, data->xwindow);
 
-        /* Now grab the keyboard */
-        XGrabKeyboard(display, data->xwindow, True, GrabModeAsync,
-                      GrabModeAsync, CurrentTime);
+        /* Now grab the keyboard if we're using old-style fullscreen */
+        if (oldstyle_fullscreen) {
+            XGrabKeyboard(display, data->xwindow, True, GrabModeAsync,
+                          GrabModeAsync, CurrentTime);
+            data->kbd_grabbed = SDL_TRUE;
+        }
     } else {
         XUngrabPointer(display, CurrentTime);
-        XUngrabKeyboard(display, CurrentTime);
+        /* Release the keyboard if we grabbed it */
+        if (data->kbd_grabbed) {
+            XUngrabKeyboard(display, CurrentTime);
+        }
     }
 }
 
diff -r 9a65b2bd4e01 src/video/x11/SDL_x11window.h
--- a/src/video/x11/SDL_x11window.h	Mon Jun 04 12:31:14 2012 -0400
+++ b/src/video/x11/SDL_x11window.h	Tue Jun 12 14:42:31 2012 +0800
@@ -38,6 +38,7 @@
     GC gc;
     XIC ic;
     SDL_bool created;
+    SDL_bool kbd_grabbed;
     struct SDL_VideoData *videodata;
 } SDL_WindowData;