Some minutes ago Firefox crashed and I saw Windows freeing up more than 6 GB of memory. After the restart I checked the task manager and the problem persisted: every few seconds there is a short peak with 25% CPU usage (which apparently accounts for full usage of one core of my quad core CPU) and the memory usage increases slowly. The memory usage is interrupted by a partial drop after a few minutes but ultimately it increases until all of the system memory is eaten up and the browser crashes again.
To narrow down the problem I started by diasbling all add-ons until the problem vanished. This allowed me to reenable all add-ons except Kee (version 2.2.9). I could narrow the problem down to this page:
https://www.computerbase.de/2018-03/antec-be-quiet-cougar-oberklassenetzteile-test/3/
Changing the logging in Kee to debug logging I get this in the console:
port already set to: page
common.js:215:17
In browser content page script, received message from background script
common.js:197:17
Logging system config updated at Thu Mar 22 2018 18:10:26 GMT+0100
common.js:206:17
Messaging port was not established at page startup. Retrying now...
common.js:206:17
port already set to: page
common.js:215:17
Messaging port was not established at page startup. Retrying now...
common.js:206:17
port already set to: page
common.js:215:17
Messaging port was not established at page startup. Retrying now...
common.js:206:17
port already set to: page
common.js:215:17
In browser content page script, received message from background script
common.js:197:17
Logging system config updated at Thu Mar 22 2018 18:10:26 GMT+0100
common.js:206:17
In browser content page script, received message from background script
common.js:197:17
Logging system config updated at Thu Mar 22 2018 18:10:26 GMT+0100
common.js:206:17
Messaging port was not established at page startup. Retrying now...
This never stops. The messages keep on coming.
I wanted to get this error report out before investigating the situation any further. I will now check with a portable version of Firefox with only Kee installed and then try with older versions. There will be updates to this initial report.
Update: The problem could be reproduced with Portable Firefox 59.0.1 and just the Kee add-on 2.2.9 installed when loading the page that is linked above. The browser did not crash after 20 minutes, but the CPU spikes were there and the memory usage kept increasing.
The problematic page:
Second update: The problem also occurs with Kee 2.1 and 2.0.