I just ran into a similar problem. Installed keepass2, which depended on mono and now sloppy focus does not work, even though it is configured.
$ cat /etc/linuxmint/info RELEASE=17.3 CODENAME=rosa EDITION="MATE 64-bit" DESCRIPTION="Linux Mint 17.3 Rosa" DESKTOP=MATE TOOLKIT=GTK
$ gsettings get org.mate.Marco.general focus-mode 'sloppy'
I just ran into a similar problem. Installed keepass2, which depended on mono and now sloppy focus does not work, even though it is configured.
$ cat /etc/linuxmint/info
RELEASE=17.3
CODENAME=rosa
EDITION="MATE 64-bit"
DESCRIPTION="Linux Mint 17.3 Rosa"
DESKTOP=MATE
TOOLKIT=GTK
$ gsettings get org.mate. Marco.general focus-mode
'sloppy'