CEF error

[Floriian]

Hi, 

I write a dashboard. I enabled the CEF-Debugging, and I always get this:

events.js:2 Uncaught TypeError: Cannot read property 'new' of undefined
    at events.js:2

Here's the events.js:

let devWindow = {
	browser: mp.browsers.new("package://dashboard/index.html"),
	keyCode: 0x7B,
	windowOpen: false
}
devWindow.browser.active = devWindow.windowOpen;


// keyDown
mp.keys.bind(devWindow.keyCode, true, function(){
		devWindow.browser.active = !devWindow.windowOpen;
		devWindow.windowOpen = !devWindow.windowOpen;
		let name = player.name;
		let money = player.money;
		devWindow.execute(`dash_update('dashboard_update(${name}, ${money});`);
});;

mp.events.add('clientLog', (logObj) => {
	if (devWindow.browser)
		devWindow.browser.execute(`addOutput('${logObj}');`);
});