[RB Plugin]How to get RB delete event correctly

Hi,

     I'm new to Rhythmbox plugin development. I'm writting a plugin 
which hook the delete event.
     When click the  'X' button, if rb is playing music currently then 
just hide the window, otherwise quit it.

     For now, I use RBShell->window, and connect to delete-event, sure 
it can achieve my goal.
     But I guess this will cause memory leak or any other bugs, at least 
the Remember-the-rhythmbox won't work correctly.

     Is there any way to do this work? Or what should I do in my 
delete-event hook.

     Thanks

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Regards

Weitian