code: private void jTreeGraph1MouseClicked(java.awt.event.MouseEvent evt)//GEN-FIRST:event_jTreeGraph1MouseClicked
      {//GEN-HEADEREND:event_jTreeGraph1MouseClicked
          if (evt.getClickCount() == 2) {
              TreePath[] paths = jTreeGraph1.getSelectionPaths();
              if (paths != null && paths.length == 1) {
                  if (paths[0].getPath().length == 3) {
                      addItemsToComposite(paths);
                  }
              }
          }
      }
docs: GEN-LAST:event_jButtonRemoveActionPerformed