IStructuredSelection iss = (IStructuredSelection) selection;
if (iss.size()==1) {
Object element = iss.getFirstElement();
if (element instanceof JcrNode) {
final JcrNode n = (JcrNode)element;
if (n.canBeCopiedToClipboard()) {
action.setEnabled(true);
this.node = n;
return;
}
}