void (@NotNull AnActionEvent e) { Project project = e.getProject(); if (project == null) return; IElementType[] allTypes = IElementType.enumerate(IElementType.TRUE); String text = Arrays.stream(allTypes) .map(t -> t.getLanguage().getID() + " " + t.getClass() + " " + t.getDebugName()) .collect(Collectors.joining("\n")); LightVirtualFile file = new LightVirtualFile("IElementType.txt", PlainTextFileType.INSTANCE, "COUNT: " + allTypes.length + "\n" + text); FileEditorManager fileEditorManager = FileEditorManager.getInstance(project); if (!fileEditorManager.isFileOpen(file)) { fileEditorManager.openEditor(new OpenFileDescriptor(project, file), true); } }