void (@NotNull final AnActionEvent e) { final Presentation presentation = e.getPresentation(); presentation.setEnabled(false); final TreePath selectionPath = myTree.getSelectionPath(); if (selectionPath != null) { final DefaultMutableTreeNode treeNode = (DefaultMutableTreeNode)selectionPath.getLastPathComponent(); if (treeNode.getUserObject() instanceof ScopeConfigurable) { if (myDirection < 0) { presentation.setEnabled(treeNode.getPreviousSibling() != null); } else { presentation.setEnabled(treeNode.getNextSibling() != null); } } } }