Hello. I have read through whole platform.netbeans.org

and I do not find how to add some instance to existing children. I can add static array of diagrams(created in addNotify()), but how to add new Diagram object to the Children? I want to add it from an action that I will create(not included in code). See the code:

public class ExploirerTopComponent extends TopComponent implements ExplorerManager.Provider {

...
...
...

public ExploirerTopComponent() {
    ...
    ...
    associateLookup (ExplorerUtils.createLookup(mgr, getActionMap()));
    mgr.setRootContext(new MyProjects());//
    setDisplayName ("Projects explorer");

}

public class MyProjects extends AbstractNode {

public MyProjects(MainProject obj) {
    super (new ProjectsChildren(), Lookups.singleton(obj));
    setDisplayName ( obj.getName());
}

public MyProjects() {
    super (new ProjectsChildren());
    setDisplayName ("My projects");
}
}

.

public class ProjectsChildren extends Children.Keys{
public ProjectsChildren() {    }


    @Override
    protected Node[] createNodes(Object o) {
        MainProject obj = (MainProject) o;
        return new Node[] { new MyDiagrams() };

    }

   @Override
protected void addNotify() {
       Diagram[] d = new Diagram[3];
       for (int i = 0; i < pr.length; i++) {
       pr[i] = new Diagram("digram");
       }
setKeys (pr);
}

}