Sets func to be called when a popup is about to be shown.
func should use one of
to set a popup for menu_button. If func is non-null, menu_button will always be sensitive.
Using this function will not reset the menu widget attached to menu_button. Instead, this can be done manually in func.
function to call when a popup is about to be shown, but none has been provided via other means, or null to reset to default behavior.
Sets func to be called when a popup is about to be shown.
func should use one of
to set a popup for menu_button. If func is non-null, menu_button will always be sensitive.
Using this function will not reset the menu widget attached to menu_button. Instead, this can be done manually in func.