Zotero 7 Beta - Problem with closing tabs

The title says it all, the pdf tabs I was reading are refusing to close (or even to change from one to another). I'm not being able even to go back to my library.

As a note, I had some tabs open before upgrading v.7.

Zotero 7.0.0-beta.14+f1003a1d1 (64-bit)
Windows 11
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