BOptionPopUp: call the superclass AttachedToWindow.

It's ther that the view background color is inherited from the parent.
Fix option popups having a white background eg. in MediaPlayer
preferences.

Thanks to DeadYak for noticing the problem.

src/kits/interface/OptionPopUp.cpp

@@ -197,6 +197,8 @@ BOptionPopUp::AllAttached()
 void
 BOptionPopUp::AttachedToWindow()
 {
+	BOptionControl::AttachedToWindow();
+
 	BMenu* menu = fMenuField->Menu();
 	if (menu != NULL) {
 		float labelWidth = fMenuField->StringWidth(fMenuField->Label());