'Populate the workspace view. Also select by default
self.default_selection (see workspace_model method). Also connect
a selection with the change workspace callback'

@scrollable(width=160)
def create_ws_view(self, model):

    self.ws_view = Gtk.TreeView(model)
    self.ws_view.set_activate_on_single_click(False)
    renderer = Gtk.CellRendererText()
    column = Gtk.TreeViewColumn('Workspaces', renderer, text=0)
    self.ws_view.append_column(column)
    self.ws_view.set_search_entry(self.search_entry)
    if (self.default_selection is not None):
        self.select_default = self.ws_view.get_selection()
        self.select_default.select_iter(self.default_selection)
    selection = self.ws_view.get_selection()
    selection.set_mode(Gtk.SelectionMode.BROWSE)
    self.ws_view.connect('button-press-event', self.on_right_click)
    self.ws_view.connect('row-activated', self.on_left_click)
    return self.ws_view
