Set<PsiFile> (final Tree tree) { TreePath[] paths = tree.getSelectionPaths(); if (paths == null || paths.length != 1) return EMPTY_FILE_SET; PackageDependenciesNode node = (PackageDependenciesNode)paths[0].getLastPathComponent(); if (node.isRoot()) return EMPTY_FILE_SET; Set<PsiFile> result = new HashSet<>(); node.fillFiles(result, true); return result; }