So me and @orgodemir did some experimenting with Fog Collision SW objects.
F3 seems to determine what effect the object will emit. Here's a table. All the numbers that aren't listed remove the passive map fog. (e.g. They will remove Caves 1 orange glow). Function is the doorID\SwichID that toggle the fog on\off. So if you set Function to 3, the fog will turn off when you call "unlock 3" via map events. We only tested F3 values up to 201. If there's anything we missed, feel free to comment. Also, if anyone knows what F4 does, please share. We haven't had time to mess around with that yet.
For some seabed rooms it appears you need to add 0x1000 to the value to get it to show up.