BOptionPopUp: move mennu setup to AttachedToWindow

* There is no need to delay this to AllAttached
* Apps may want to override the SetDivider, and doing it as late as
AllAttached can be annoying.

Fixes #10734.

headers/os/interface/OptionPopUp.h

@@ -27,7 +27,7 @@ public:
 								BOptionPopUp(const char* name,
 									const char* label, BMessage* message,
 									uint32 flags = B_WILL_DRAW);
-								
+
 	virtual						~BOptionPopUp();
 
 			BMenuField*			MenuField();
@@ -40,6 +40,7 @@ public:
 									int32 index);
 
 	virtual	void				AllAttached();
+	virtual	void				AttachedToWindow();
 	virtual	void				MessageReceived(BMessage* message);
 	virtual	void				SetLabel(const char* text);
 	virtual	void				SetValue(int32 value);
@@ -47,7 +48,7 @@ public:
 	virtual	void				GetPreferredSize(float* _width,
 									float* _height);
 	virtual	void				ResizeToPreferred();
-		
+
 	virtual	int32				SelectedOption(const char** _name = 0,
 									int32* _value = 0) const;
 private: