UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36

Steps to reproduce the problem:
1. Configure an authenticated proxy via group policy or manually.
2. Configure a startup tab to google.com via group policy or manually.
3. Close all instances of Chrome.
4. Open Chrome.

What is the expected behavior?
The proxy authentication modal should appear, prompting for a username and password.

What went wrong?
The startup page, (Google in this instance) is requested before the proxy is authenticated.

The string "Web proxy authentication failed" is rendered in the browser tab.

The modal does not pop up.

One then has to browse in a new tab, or resubmit the request to google.com or press F5 to trigger a second HTTP request for the modal to appear, at which point one can properly authenticate.

Did this work before? No 

Chrome version: 49.0.2623.112  Channel: stable
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: Shockwave Flash 21.0 r0

In actual fact, the modal does appear for the instant before the initial tab request is made. The failed authentication then causes the modal to close. This usually occurs before the modal can draw itself, and so on does not see it often.

This may appear minor, however in setting up 300 individuals with this type of access, an average of 50% actually originated that they could not connected, and had to be instructed to reload the page to receive the proxy authentication request.

From a UX perspective, I believe this is important to get handled.