What's "Scanning Libraries"?

I am currently creating items in library and when I save, there’s a progress bar with “Scanning Libraries…” message.

I is a bit long. Is it normal ?

And my main question, should I wait the end of this scan before closing the tab / window ?

Thanks.

Unless you are editing a library it is a don’t care.

If you are editing a library then you must wait for it to finish in order for the display to catch up with your edits, otherwise things look wrong.