@Override public void componentSelected(MenuEvent ce) { GPBeanTreeModel item = (GPBeanTreeModel) this.treePanel.getSelectionModel().getSelectedItem(); if (item instanceof FolderTreeNode) { FolderTreeNode selectedFolder = (FolderTreeNode) item; if (!selectedFolder.isLoaded()) { this.selectedElement = (FolderTreeNode) item; this.confirmExpandingMessage(); } else { this.execute(selectedFolder.getChildren(), selectedFolder.getLabel()); } } else { throw new IllegalArgumentException( "The CreateFolderViewportAction can " + "take only folder and not layer"); } }