Version: 51.0.2692.0
OS: ChromeOS

What steps will reproduce the problem?
(1) Open gmail.com & sign-in.
(2) Click to pop-out the Tasks area.
(3) Select an email and click to pop it out into a window.

What is the expected output?

Both the email & Tasks windows popped-out do not load.

In the case of Tasks, the Tasks area in the main GMail tab stays active (presumably it is hidden in response to the popped-out view loading).

Marking "Site-Isolation" in case it's related to those experiments.