As per #267 we agreed that this pref makes little sense. Especially as we're considering to move the project session files to a completely separate file (so neither geany.conf nor $project.geany).
Currently, if not checked, the project session files would be stored in the (new) session.conf file, overwriting the non-project session. This is what #267 is about. You can view, comment on, or merge this pull request online at:
https://github.com/geany/geany/pull/3125
-- Commit Summary --
* Remove pref "Use project-based session files", now always enabled
-- File Changes --
M data/geany.glade (16) M src/keyfile.c (2) M src/libmain.c (2) M src/prefs.c (6) M src/project.c (54) M src/project.h (1)
-- Patch Links --
https://github.com/geany/geany/pull/3125.patch https://github.com/geany/geany/pull/3125.diff