if (virtualFile == null) return;
Project project = bnfFile.getProject();
installUpdateListener(project);
FileEditorManagerEx fileEditorManager = FileEditorManagerEx.getInstanceEx(project);
EditorWindow curWindow = fileEditorManager.getCurrentWindow();
curWindow.split(SwingConstants.HORIZONTAL, false, virtualFile, true);
fileEditorManager.openFile(virtualFile, true);
}