* src/widgets/modest-window-mgr.c:

* src/widgets/modest-window-mgr.c:
        * As ..._unregister_window frees the g_list node, changed the
          order to fetch first the next element in list before we
          destroy the reference to the list.
        * Now on_window_destroy never propagates, as we take care of
          destroy.
        * The window mgr window list contains now a explicit GObject
          reference, and we free this one on removing elements from it.
* src/modest-ui-actions.c:
        * On creating view and edit windows, we don't unref them as
          these references are the floating ones (handled by gtk).
* src/modest-main-window.c:
        * Keep an explicit reference to empty view and header view
          to be able to free them properly on finishing the main
          window.
        * Fix a reference leak to folder store on calling to sync folder
          mail operation.

pmo-trunk-r4766