diff -ur qt-everywhere-opensource-src-4.6.3/src/gui/kernel/qguieventdispatcher_glib.cpp qt-everywhere-opensource-src-4.6.3-glib_eventloop_nullcheck/src/gui/kernel/qguieventdispatcher_glib.cpp
--- qt-everywhere-opensource-src-4.6.3/src/gui/kernel/qguieventdispatcher_glib.cpp	2010-06-02 04:03:15.000000000 +0200
+++ qt-everywhere-opensource-src-4.6.3-glib_eventloop_nullcheck/src/gui/kernel/qguieventdispatcher_glib.cpp	2010-12-08 22:22:38.000000000 +0100
@@ -76,7 +76,7 @@
     GX11EventSource *source = reinterpret_cast<GX11EventSource *>(s);
     return (XEventsQueued(X11->display, QueuedAfterFlush)
             || (!(source->flags & QEventLoop::ExcludeUserInputEvents)
-                && !source->d->queuedUserInputEvents.isEmpty()));
+                && source->d && !source->d->queuedUserInputEvents.isEmpty()));
 }
 
 static gboolean x11EventSourceCheck(GSource *s)
@@ -84,7 +84,7 @@
     GX11EventSource *source = reinterpret_cast<GX11EventSource *>(s);
     return (XEventsQueued(X11->display, QueuedAfterFlush)
             || (!(source->flags & QEventLoop::ExcludeUserInputEvents)
-                && !source->d->queuedUserInputEvents.isEmpty()));
+                && source->d && !source->d->queuedUserInputEvents.isEmpty()));
 }
 
 static gboolean x11EventSourceDispatch(GSource *s, GSourceFunc callback, gpointer user_data)
@@ -95,7 +95,7 @@
     do {
         XEvent event;
         if (!(source->flags & QEventLoop::ExcludeUserInputEvents)
-            && !source->d->queuedUserInputEvents.isEmpty()) {
+            && source->d && !source->d->queuedUserInputEvents.isEmpty()) {
             // process a pending user input event
             event = source->d->queuedUserInputEvents.takeFirst();
         } else if (XEventsQueued(X11->display, QueuedAlready)) {
@@ -112,7 +112,8 @@
                 case XKeyRelease:
                 case EnterNotify:
                 case LeaveNotify:
-                    source->d->queuedUserInputEvents.append(event);
+                    if (source->d)
+                        source->d->queuedUserInputEvents.append(event);
                     continue;
 
                 case ClientMessage:
@@ -127,7 +128,8 @@
                             break;
                         }
                     }
-                    source->d->queuedUserInputEvents.append(event);
+                    if (source->d)
+                        source->d->queuedUserInputEvents.append(event);
                     continue;
 
                 default:
@@ -140,7 +142,7 @@
         }
 
         // send through event filter
-        if (source->q->filterEvent(&event))
+        if (source->q && source->q->filterEvent(&event))
             continue;
 
         if (qApp->x11ProcessEvent(&event) == 1)
@@ -152,7 +154,8 @@
 
  out:
 
-    source->d->runTimersOnceWithNormalPriority();
+    if (source->d)
+        source->d->runTimersOnceWithNormalPriority();
 
     if (callback)
         callback(user_data);