message: Disallow multiple application windows
diff: @@ -33,6 +33,20 @@ let mainWindow: Electron.BrowserWindow;
  // Mark secure to avoid mixed content warnings when loading DigitalOcean pages via https://.
  electron.protocol.registerStandardSchemes(['outline'], {secure: true});
  +const isSecondInstance = app.makeSingleInstance((argv, workingDirectory) => {
  + // Someone tried to run a second instance, we should focus our window.
  + if (mainWindow) {
  + if (mainWindow.isMinimized()) {
  + mainWindow.restore();
  + }
  + mainWindow.focus();
  + }
  +});
  +
  +if (isSecondInstance) {
  + app.quit();
  +}
  +
  app.on('ready', () => {
  const menuTemplate = menu.getMenuTemplate(debugMode);
  if (menuTemplate.length > 0) {
  