Yes… to summarize: You’re having problems with audio playing while thumbnails are generated.
I’m trying to get the time to fix this and cut a new build. I’ve already done some legwork, and I see where some of the problem is:
1) It’s trying to get thumbnails for mms://, rtp://, udp://, etc. links, which will never work, but it waits for document load (which will never happen) for a full minute before it gives up… In the meantime, audio could start playing
2) It tries to get thumbnails for video urls (We never expected people to bookmark video files), but again, it waits for an event that will never happen for a full minute before it gives up… meanwhile… audio starts playing
4) For all three above, when the thumbnails fail to generate because it times out before document load completion, it’s going to re-try the thumbnail generation the next time you go back to that screen in bookmarks. So the cycle begins again.
5) While each thumbnail is given a minute to load the page before timeout, all the bookmarks that need new thumbnails wait their turn before that timer starts. So the effect is that each bookmark is “loading” for much longer than a minute.
6) In some cases, it looks like it’s trying to load too many thumbnails, and so it’ll just get bogged down and you may run into audio starting on one or more of the bookmarks… This needs to throttle appropriately. There’s already a preference in about:config to handle some of the throttling. You can go into about:config and look for “pagePreview.numGenerators”. Set this to 1 to prevent more than one thumbnail from being generated at once (you’ll still see multiple spinning progress indicators, but only one will be loading a page at a time).
7) It’s true that I need to adjust the expiry time for the thumbnails. It’s currently set to EXPIRE_WEEKS which is a Mozilla concept that chuck out data for unvisited links twice a month. I will definitely set that to EXPIRE_WITH_HISTORY, which will keep the data as long as you don’t flush history.
I do not yet understand this scenario of the thumbnail generation process getting kicked off on an interval while the bookmark screen is open and Kylo remains untouched. I’ll try to recreate that.
It’s pretty safe to say we never expected anyone to load up 2000 bookmarks into this thing or give it direct links to streaming URLs. And unfortunately, when “we” built this thing, “we” were more than just “me”. I am trying very hard to support this free software that I’ve grown very attached to by myself, but keep in mind that this is now officially an open community project, so it’s up to me to find personal time to work on fixing/changing things.