Unregister theming subclasses at comctl32 shutdown; should fix

reported re-registration errors.

dlls/comctl32/comctl32.h

@@ -250,6 +250,7 @@ static inline void MONTHCAL_CopyTime(const SYSTEMTIME *from, SYSTEMTIME *to)
 }
 
 extern void THEMING_Initialize(void);
+extern void THEMING_Uninitialize(void);
 extern LRESULT THEMING_CallOriginalClass(HWND, UINT, WPARAM, LPARAM);
 extern void THEMING_SetSubclassData(HWND, ULONG_PTR);
 

dlls/comctl32/commctrl.c

@@ -150,6 +150,9 @@ BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
             break;
 
 	case DLL_PROCESS_DETACH:
+            /* clean up subclassing */ 
+            THEMING_Uninitialize();
+
             /* unregister all common control classes */
             ANIMATE_Unregister ();
             COMBOEX_Unregister ();

dlls/comctl32/theming.c

@@ -146,6 +146,20 @@ void THEMING_Initialize (void)
     }
 }
 
+/***********************************************************************
+ * THEMING_Uninitialize
+ *
+ * Unregister shadow classes for standard controls.
+ */
+void THEMING_Uninitialize (void)
+{
+    int i;
+    for (i = 0; i < NUM_SUBCLASSES; i++)
+    {
+        UnregisterClassW (subclasses[i].className, NULL);
+    }
+}
+
 /***********************************************************************
  * THEMING_CallOriginalClass
  *