doesn't show in webview about electron-context-menu HOT 2 CLOSED

const electron = require('electron');
const {app, BrowserWindow, shell}  = electron;
const contextMenu = require('electron-context-menu');
...
app.on('web-contents-created', (e, contents) => {
  if (contents.getType() == 'webview') {
    // open link with external browser in webview
    contents.on('new-window', (e, url) => {
      e.preventDefault()
      shell.openExternal(url)
    })
    // set context menu in webview
    contextMenu({
      prepend: (defaultActions, params, browserWindow) => [{
        label: 'Rainbow',
        visible: params.mediaType === 'image'
      }],
      window: contents
    });
  }
});