Descriptive Problem Summary:
at /tg/ we ran into a hang when you attempt to load firebug-lite (a javascript version of firefox's f12 dev tools).

I wouldn't have reported it here, assuming it to be an IE bug, but I discovered (by accident) that the hang started to trigger in 511.1371, 511.1370 has no hang. 512.1403 was confirmed to still hang.

I used a 512.1403 server and pager when testing, only changing the client.


Numbered Steps to Reproduce Problem:
Launch world
Press lockup verb

Code Snippet (if applicable) to Reproduce Problem:
https://tgstation13.org/msoshit/firebuglockup.zip

This is the test project I originally setup to test to test this bug, it loads part of our browser based chat output (the thing we were trying to debug in firebug when this issue presented itself). Its actually missing some files, but what it contains is enough to trigger the hang.