Upgrade to Sparkle 5.5

Good morning, I am very happy that finally the site opens in seconds after upgrading to 5.5.
I noticed, however, that after opening the thumbnails of the pages on the left take their time to appear and only if you go to their page, only the dotted lines are visible on the rest. Also on closing it gets stuck as before.
Of course it could be due to my computer.

Good morning,
yeah, this might have to do with your computer. Mine is opening and displaying the site faster than ever with Sparkle 5.5.

The thumbnails are only saved if you actually make some other change that causes the project as a whole to be saved. The performance of drawing thumbnails can depend on many things, the most common issue is very large images (say multiple 6000x4000 images) on a slow Mac.