When returning to Notepad++ I got asked a number of times if I wanted to keep the documents of files that no longer existed. This was caused by me having just renamed a folder.

I wanted to keep these files open and change the paths in (a copy of) session.xml, so they would be opened upon the next launch again. I edited the session.xml and closed Notepad++.

I then compared my edited verion of session.xml with the one saved by Notepad++. I noticed the files that didn't exist anymore, weren't listed in the session.xml anymore. I would have expected them to be, because this would be of no harm when Notepad++ notices upon the next launch that these files do no longer exist.

Also, the activeIndex number that was saved was the actual number in Notepad++ with these no longer existing files documents still open. When these files are removed from the session.xml deliberately, then also the activeIndex should (have) be(en) updated. However, I'd rather see the references to all files or documents that were opened when closing Notepad++, so including these documents of which the file doesn't exist anymore.