void (@NotNull AnActionEvent event) { Presentation presentation = event.getPresentation(); Project project = event.getData(CommonDataKeys.PROJECT); if (project == null) { presentation.setEnabled(false); return; } FileEditorManagerEx fileEditorManager = FileEditorManagerEx.getInstanceEx(project); VirtualFile selectedFile; final EditorWindow window = event.getData(EditorWindow.DATA_KEY); if (window != null) { presentation.setEnabled(window.getFileList().size() > 1); return; } else { if (fileEditorManager.getSelectedFiles().length == 0) { presentation.setEnabled(false); return; } selectedFile = fileEditorManager.getSelectedFiles()[0]; } presentation.setEnabled(fileEditorManager.getSiblings(selectedFile).size() > 1); }