[KevinH]

What priorities for the QWebEngine processes are you seeing in the Task Manager when you see the slowness? The priority will only impact the speed of Preview updating because its scheduled start will be delayed due to its lowered priority, but once scheduled/started, updating will be fast.

That is consistent with the sluggishness observed by BeckyEbook as well when the first instance of Sigil is closed.

I can turn off all use of disk based caching to see if that helps, but then nothing will be remembered (ala the Inspector not remembering its language settings, if you remember that bug report).

We have used all disk based caching in the past when it was broken with no issues, and the new WebProfileBuilder is supposed to prevent a disk cache from being reused by another process.


Please check out the priority of the QWebEngine processes in the task manager and let me know what priorities you are seeing.

It does appear strange that the second instance of Sigil is generating 2 QWebEngineProcess threads instead of the expected single one.

If you get a free moment, can you test the same thing on Linux as well. If so, I may be able to recreate it there.

Maybe we should be thinking about making both Windows, and Linux versions of Sigil, use the same multiple main window approach that MacOS and Microsoft Office (all flavours) uses.

Another thing to try is actually opening multiple browser program instances, each with multiple tabs instead of just new main windows and/or just new tabs to see how that responds on Windows.

KevinH