I have done the development but am having a hard time finding the time to deploy a new version of PlantText, which supports multi-document saving. Instead of saving documents to my server or Google Drive, I coded it to save any number of documents to your computer browser local storage. I think this approach works pretty well. Anyway, look for that in a release some time in the next month. I said that I would get it out last year, but promise to do it in the next month or so for sure.
Also, I would like to make diagrams shareable, but don’t have to time to do that honestly.