part of alt-tab handling dx checkin

panda/src/display/graphicsStateGuardian.h

@@ -155,7 +155,7 @@ protected:
 
   CoordinateSystem _coordinate_system;
 
-private:
+protected:
   typedef set<TextureContext *> Textures;
   Textures _prepared_textures;
 

panda/src/display/graphicsWindow.h

@@ -133,6 +133,8 @@ PUBLISHED:
   INLINE bool has_pointer(int device) const;
   INLINE bool has_keyboard(int device) const;
 
+  virtual void process_events(void) { return; };   // process window events
+
 public:
   INLINE const MouseData &get_mouse_data(int device) const;
   INLINE bool has_button_event(int device) const;