I use NValt to create, search and organize my notes,
and I love Foldingtext.
Switching to encrypted single file database in NValt makes Foldingtext unusable in the “edit with” (external editor) menu/command.
This not only happens with FT, and some editors work, but I only need it for FT… Someone suggested that the editor has to support the ODB Editor Suite… see here:
https://github.com/scrod/nv/issues/287
Would be great if this were an easy fix on FTs side …!!! 
Or does someone have other tips?!