Preview app sidebar bug (OS 14.6.1)
I will explain with an example: I have Preview open with 3 tabs. I chose to "Hide Sidebar" to one of them. I go to a different one or open a new pdf, in which the sidebar is not hidden (or I don't want it hidden for this specific pdf). Going back to the other pdfs, they now all show the sidebar. Additionally, "hide sidebar" is checked, so to hide it, you need to click on something else from the "view" and then select "hide sidebar" again.
MacBook Pro 13″, macOS 14.6