Selecting Multiple GoNodes inside a subgraph


I want to select multiple nodes in side a subgraph and modify the common properties for all the nodes. I'm able to select the multiple nodes by setting the pickablebackground = false. But when I right click on any selected node only that is selecting and all other nodes are deselecting.
Please help me on this.

GoToolContext has an option (SingleSelection) to turn off select on mouse down.

(myView.FindMouseTool(typeof(GoToolContext), true) as GoToolContext).SingleSelection = false;

Thank You Jake. It works.