I’ve found that Notepad++ prevents me from deleting directories if I have previously opened a file in that directory. I still cannot delete the directory even if the file is closed in Notepad++. I talked to a Windows-savvy friend of mine, and he says that this is because Windows “Open File” dialogues change the program’s current directory to the opened file’s directory. That way, when you open another file you get the most recently used directory. But, the program now prevents anyone from deleting or renaming that directory.
It would be nice if Notepad++ would restore its original working directory after an Open File dialogue closes. Then, it could switch back to the most recently used directory the next time the Open File dialogue is invoked, so that the behavior remains the same.
I have no trouble deleting the directory/folder in such a case, with Win7 64bit and Notepad++ 7.3.3 32bit at least. Maybe the way I tried it is different from your use-case where you see an issue–can you post more detail about what you do to see this happen? Maybe that sounds dumb, but bear with me–people often leave out a crucial step that seems so obvious to them, but isn’t at all to others.
What error do you get when trying to delete the directory? A “Folder In Use” box with “Try Again” and “Cancel” buttons?