paintWhenInitiallyHidden

main.js

const {app, BrowserWindow} = require('electron')

let mainWindow

function createWindow () {
  mainWindow = new BrowserWindow({
    width: 800,
    height: 600,
    show: false,
    paintWhenInitiallyHidden: false,
    webPreferences: {
      contextIsolation: true,
      sandbox: true,
    }
  })

  mainWindow.loadURL('https://www.google.com')

  mainWindow.hide()
}

app.on('ready', createWindow)

app.on('window-all-closed', function () {
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', function () {
  mainWindow.show()
  mainWindow.focus()
})