diff --git a/graf2d/qt/inc/TQtApplication.h b/graf2d/qt/inc/TQtApplication.h
index 07593c7c382a662dc0ceb2353b99fe68e4232d70..17a0912889e4663f3ee375f436851d69edeae966 100644
--- a/graf2d/qt/inc/TQtApplication.h
+++ b/graf2d/qt/inc/TQtApplication.h
@@ -44,7 +44,7 @@ protected:
 
 public:
 
-   TQtApplication() {};
+   TQtApplication() {fGUIThread=0;};
    TQtApplication(const char *appClassName, int &argc, char **argv);
    virtual ~TQtApplication();
    static bool Terminate();