def _left_up ( self, event ):
        window = self.control
        if self._owner is not None:
            window.ReleaseMouse()
            self._owner.mouse_up( event )
            self._owner = None

        # Check for the user requesting that the layout structure be reset:
        if event.ShiftDown():
            if event.ControlDown():
                # Check for the developer requesting a structure dump (DEBUG):
                if event.AltDown():
                    contents = self.sizer.GetContents()
                    if contents is not None:
                        contents.dump()
                        sys.stdout.flush()
                else:
                    self.sizer.ResetStructure( window )
                    self.update_layout()
            elif event.AltDown():
                self.sizer.ToggleLock()
                self.update_layout()

    #---------------------------------------------------------------------------
    #  Handles the left mouse button being double clicked:
    #---------------------------------------------------------------------------
Handles the left mouse button being released.
dataset/ETHPy150Open enthought/pyface/pyface/dock/dock_window.py/DockWindow._left_up