Oh noes :c
I thought Gmod would have downloaded it.
Nope. :c
New feature that
requiers you to manually download whatever map the server is using or you're automatically DC'd when the server detects it's missing from your maps folder.
Really gay because I hate having to completely download an entire map just to join a server that might have some gm_flatgrass edit.
If he wanted to download from the server he just needs to go to Options>Multiplayer>Bottom right>"Download All custom files from server"
Maybe this, but I don't think the downloader in-game is able to get every texture placed in the map, plus it takes longer.