Why is my Preview app Sidebar not refreshing?

I use the Preview app a lot to open files of multiple images, click on the thumbnails in the sidebar to view them at large size, then right click on the thumbnail and Move to Bin for those I want to delete.

Since I updated to Sequoia, Preview has got flaky - when I Move To Bin, the actual image file is moved from its folder to the bin, but its thumbnail in Preview doesn't always delete, which is making things confusing.

(I have to close and reopen the sidebar for it to refresh correctly, which is long-winded and frustrating with a large file of images to check).

I have tried deleting the preference file, but it's still not working as it should/used to.

Any ideas, please?

[Re-Titled by Moderator]