I'm trying to figure out why my FormattingService implementing AsyncDocumentFormattingService is not invoked whenever I tried to reformat multiple files (e.g. a whole folder). Also, it isn't possible to get my files to reformat on save (my filetype isn't shown in the Setting > Tools > Action on Save option for "Reformat Code"). I have implemented my service as outlined in the documentation and for single files in works perfectly (even keeping the cursor at a reasonable position most of the time).
Is reformatting multiple files only supported when I implement the Format Model Builder? Any workaround for this?