Chrome on macOS Sierra - Issues with initial terminal load

[tokiwinter]

I am experiencing an issue on macOS Sierra 10.12.4, which has been reproduced in Chrome 57.x (not sure of exact version as I upgraded it to try to resolve this issue) and 58.0.3029.110 (64-bit). Upon clicking the "Terminal: LOGIN" button, I receive a blank browser window (see attached upload). If I resize the browser slightly, the terminal loads and I am successfully logged into the host.

This is vague, I know, but I have enabled debug logging on the host, and can of course provide any debugging information required (logs, command output, whatever you need).

A colleague on Windows is not experiencing this issue. I'm running up an Ubuntu 17.04 VM now and will test on that too once it's provisioned.

[tokiwinter]

From the host:

# /opt/virtualenvs/gateone/bin/pip freeze
appdirs==1.4.3
backports-abc==0.5
backports.ssl-match-hostname==3.5.0.1
certifi==2017.4.17
futures==3.1.1
gateone==1.2.0
html5lib==0.999999999
packaging==16.8
pyparsing==2.2.0
singledispatch==3.4.0.3
six==1.10.0
tornado==4.5.1
webencodings==0.5.1

We're installing from wheels built from the following GateOne commit and its dependencies:

git+git://github.com/liftoff/GateOne@00e810bcda3f254af094a4cbe54dd77c9a4df23c#egg=GateOne

On a much older version of GateOne (which we are trying to upgrade, hence uncovering this issue), this problem does not occur.