First of all, thank for your work. You do a great job!
I contact you to suggest a new evolution related to the design of "tabbed files".
You should add a functionality which allow user to organise his files (opened in NP++) in folder, so as to easily browse between many files.
Rather than having as many tab as file, having possibility to move some of them in a folder in "navigation bar".
Like directory in Firefox bookmarks. Having a directory (if user choose it) per project which contain relative opened sources.
Good continuation and thank for your time!