diff --git a/src/kernel/ntqobject.h b/src/kernel/ntqobject.h
index fc16c50b..19df5472 100644
--- a/src/kernel/ntqobject.h
+++ b/src/kernel/ntqobject.h
@@ -237,6 +237,7 @@ public:
 #endif
 
 private:
+    void cleanupControlElementData();
 #ifdef TQT_THREAD_SUPPORT
     void moveToThread_helper(TQThread *targetThread);
     void setThreadObject_helper(TQThread *targetThread);
diff --git a/src/kernel/qapplication.cpp b/src/kernel/qapplication.cpp
index e8658cda..87d4fd7d 100644
--- a/src/kernel/qapplication.cpp
+++ b/src/kernel/qapplication.cpp
@@ -1203,6 +1203,12 @@ TQApplication::~TQApplication()
     tqt_desktopWidget = 0;
     is_app_closing = TRUE;
 
+    // Due to hacks to spead up TQStyle engine (see git hash 523c1fd99) TQObjects now contain a
+    // reference to TQStyleControlElementData object which among other contain TQFont members.
+    // But for a proper cleanup all fonts should be destroyed before disconnecting from X11 (in
+    // tqt_cleanup()). So we will have to cleanup up the data explicitly.
+    cleanupControlElementData();
+
 #ifndef TQT_NO_CLIPBOARD
     delete tqt_clipboard;
     tqt_clipboard = 0;
diff --git a/src/kernel/qfont_x11.cpp b/src/kernel/qfont_x11.cpp
index 9f86734a..3cd207c6 100644
--- a/src/kernel/qfont_x11.cpp
+++ b/src/kernel/qfont_x11.cpp
@@ -312,6 +312,7 @@ void TQFont::cleanup()
 {
     // delete the global font cache
     delete TQFontCache::instance;
+    TQFontCache::instance = 0;
 }
 
 /*!
diff --git a/src/kernel/qobject.cpp b/src/kernel/qobject.cpp
index 3ab2d9b9..bb4c848b 100644
--- a/src/kernel/qobject.cpp
+++ b/src/kernel/qobject.cpp
@@ -134,6 +134,13 @@ TQStyleControlElementDataPrivate* TQObject::controlElementDataPrivateObject() {
 	return d->controlElementDataPrivate;
 }
 
+void TQObject::cleanupControlElementData() {
+    delete d->controlElementData;
+    d->controlElementData = 0;
+    delete d->controlElementDataPrivate;
+    d->controlElementDataPrivate = 0;
+}
+
 #if defined(TQT_THREAD_SUPPORT)
 
 void TQObject::moveToThread_helper(TQThread *targetThread)
diff --git a/src/kernel/qrichtext_p.cpp b/src/kernel/qrichtext_p.cpp
index 4411b4d4..022eb13d 100644
--- a/src/kernel/qrichtext_p.cpp
+++ b/src/kernel/qrichtext_p.cpp
@@ -337,6 +337,19 @@ int TQTextFormat::pntr_asc=-1;
 int TQTextFormat::pntr_hei=-1;
 int TQTextFormat::pntr_dsc=-1;
 
+void TQTextFormat::cleanupPrivateData() {
+    delete TQTextFormat::pntr_fm;
+    TQTextFormat::pntr_fm = 0;
+    TQTextFormat::pntr = 0;
+
+    // Not really necessary, but better to tidy-up everything
+    TQTextFormat::pntr_fm = 0;
+    TQTextFormat::pntr_ldg=-1;
+    TQTextFormat::pntr_asc=-1;
+    TQTextFormat::pntr_hei=-1;
+    TQTextFormat::pntr_dsc=-1;
+}
+
 void TQTextFormat::setPainter( TQPainter *p )
 {
     pntr = p;
@@ -350,10 +363,16 @@ TQPainter*  TQTextFormat::painter()
 void TQTextFormat::applyFont( const TQFont &f )
 {
     TQFontMetrics fm( pntr->fontMetrics() );
+
+    if ( !pntr_fm ) {
+	tqAddPostRoutine( &TQTextFormat::cleanupPrivateData );
+    }
+
     if ( !pntr_fm
 	|| pntr_fm->painter != pntr
 	|| pntr_fm->d != fm.d
-	|| !pntr->font().isCopyOf( f ) ) {
+	|| !pntr->font().isCopyOf( f )
+       ) {
 	pntr->setFont( f );
 	delete pntr_fm;
 	pntr_fm = new TQFontMetrics( pntr->fontMetrics() );
diff --git a/src/kernel/qrichtext_p.h b/src/kernel/qrichtext_p.h
index df6b0a27..428b0ec5 100644
--- a/src/kernel/qrichtext_p.h
+++ b/src/kernel/qrichtext_p.h
@@ -1561,6 +1561,7 @@ protected:
 private:
     void update();
     static void applyFont( const TQFont &f );
+    static void cleanupPrivateData();
 
 private:
     TQFont fn;
diff --git a/src/styles/qcommonstyle.cpp b/src/styles/qcommonstyle.cpp
index a9bfbcf2..f5c57d46 100644
--- a/src/styles/qcommonstyle.cpp
+++ b/src/styles/qcommonstyle.cpp
@@ -165,6 +165,10 @@ static TQString TQFrame_static_string("TQFrame");
 static TQString TQWidget_static_string("TQWidget");
 
 static TQStyleControlElementData* TQStyleControlElementData_null = NULL;
+static void tqt_style_control_element_data_null_cleanup() {
+    delete TQStyleControlElementData_null;
+    TQStyleControlElementData_null =0;
+}
 
 #include <ntqmetaobject.h>
 
@@ -805,6 +809,7 @@ const TQStyleControlElementData &populateControlElementDataFromWidget(const TQWi
 	else {
 		if (!TQStyleControlElementData_null) {
 			TQStyleControlElementData_null = new TQStyleControlElementData();
+			tqAddPostRoutine(tqt_style_control_element_data_null_cleanup);
 		}
 		TQStyleControlElementData &ceData = *TQStyleControlElementData_null;
 		return ceData;