Multiple Selection DnD class.py

class MultiDragDropTreeView(DragDropTreeView):
	'''TreeView that captures mouse events to make drag and drop work properly'''

	def __init__(self):
		super(MultiDragDropTreeView, self).__init__()
		
		self.connect('button_press_event', self.on_button_press)
		self.connect('button_release_event', self.on_button_release)
		self.defer_select = False

	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]
			
	def on_button_release(self, widget, event):
		# re-enable selection
		self.get_selection().set_select_function(lambda *ignore: True)
		
		target = self.get_path_at_pos(int(event.x), int(event.y))	
		if (self.defer_select and target 
		   and self.defer_select == target[0]
		   and not (event.x==0 and event.y==0)): # certain drag and drop
			   self.set_cursor(target[0], target[1], False)
			
		self.defer_select=False