def on_button_press(self, widget, event):
        # Here we intercept mouse clicks on selected items so that we can
        # drag multiple items without the click selecting only one
        target = self.get_path_at_pos(int(event.x), int(event.y))
        if (target
           and event.type == gtk.gdk.BUTTON_PRESS
           and not (event.state & (gtk.gdk.CONTROL_MASK|gtk.gdk.SHIFT_MASK))
           and self.get_selection().path_is_selected(target[0])):
            # disable selection
            self.get_selection().set_select_function(lambda *ignore: False)
            self.defer_select = target[0]
dataset/ETHPy150Open ejeschke/ginga/ginga/gtkw/GtkHelp.py/MultiDragDropTreeView.on_button_press/original