Garry's mod and HL2: DM

I have this “weird” problem with Garry’s Mod, being that it always mounts HL2: DM (even though it’s not even installed), no matter how many times I untick it.
Because of this it also always downloads a part of HL2:DM.

Anyone got a solution?

Well, you can get the game for free, that’s the solution. Google ATi/nVidia Steam offer.

I own the game, thing is I do NOT want it to be mounted at this time.

It’s not actually downloading HL2DM it’s just downloading it’s Source Base Content, don’t worry about it.

I noticed it’s not a huge download, and that’s not the issue at hand either.
It is possible to untick Half life 2: deathmatch in gmod settings, but no matter what, it gets added anyway and reticked upon restart.