Hi, So, everyone seems to have this issue exactly with version 1.20.0-2. It's the version where 2003_fake_xdg_current_desktop.patch had been added [1]. I've done some testing and I can say this patch does the wrong thing. See my comment with screenshot at [2] for more info.
Therefore I suggest removing that patch. Side note: in [2] I've mentioned only testing in Ubuntu-based system, but I've got the same result in current Debian Testing. [1] https://salsa.debian.org/debian-mate-team/caja-dropbox/commit/d21f44fbcf1b6e41123dc3b216a0e37cafec63d5 [2] https://github.com/mate-desktop/caja-dropbox/issues/27#issuecomment-451727829
