Prevent MATE from launching Caja Desktop when running i3

A while back I installed i3 on my MATE box, and I'm quite happy with it, however despite disabling Caja Desktop (x-caja-desktop) when setting i3 as the default window manager through dconf editor, every time I install a .deb package via the gui installer, the desktop "window" opens and overlays my entire screen. This is incredibly annoying, and hitting super-shift-q to close the window doesn't work, which forces me to just move it to an unused workspace. Is there anything I can do to stop this from happening without installing a different file manager?