I noticed this while trying out the application today.
To recreate all I have to do is click "Show History" and then "Close All". It leads to runaway memory consumption (on my system the tab dies after 9gb). Not sure what is causing it as I've only just started playing with this application.
I'll keep poking around as I have time and try to understand what is occurring.
I'm on Ubuntu 16.04 and I'm running this in Chrome version 59.0.3071.115