Thanks for the clear bug report. I was able to reproduce the problem on that website and think that I have implemented a fix.
The fix is included in the latest development version of Kee 3.8 - Release 3.8.1 · kee-org/browser-addon · GitHub
I won’t have time to thoroughly test it for at least a week or two so it won’t make it into the upcoming Kee 3.7 but if someone can confirm the problem is resolved in that development version, that will speed along the process of releasing 3.8 to beta testers, once they’ve had a chance to test the changes in 3.7 that are rolling out now.
Installing development versions of Kee requires jumping through some hoops such as using a pre-release version of Firefox so don’t worry if you can’t test it - I will eventually get around to doing so myself.
For anyone interested in the technical details, it turns out that Firefox and Chrome inject the scripts that Kee runs on webpages into SVG images as well as webpages. I can’t find much in the way of documentation about this behaviour, nor any way to customise it but I found what I think is a way to prevent the Kee script from doing anything significant when it is mistakenly asked to execute inside an SVG.
The reason that this could lead to runaway CPU usage and memory growth is not clear but I suspect it relates to how Kee has to re-execute some parts of its startup code in certain circumstances (there are - at least in older browser versions - several bugs in Firefox and Chrome that we have to work around).
I have a further idea to reduce this impact of failed script startup which I will explore in the coming weeks and hope to include in Kee 3.8 - that might help in situations where the reason for the startup failure is not due to being injected into an SVG.