Setup golang environment using jetbrains

I have setup an golang developing envionemnt using idea (13.1 community edition).
It seems the SDK is recognized.
However, I could not create a GO file by right click the "New" under the source folder. (The item of "go" is grayed)
Currently I have to manually set the file extension to ".go" and edit the file, but autocomplete is OK.
This only exist on my Mac(with version 10.9.4)
I have set the GOPATH directory access mode to 777 but still not work.
This works fine on windows7.
So what should I do ?

This is what it looks like in windows

Thanks VonC, I already tried the /Users/Tom/go setting, this doesn't work and I switch to this root path.
here's my previous setting

 macbook:home root# go env
GOARCH="amd64"
GOBIN=""
GOCHAR="6"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/mac/go"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/darwin_amd64"
CC="clang"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fno-common"
CXX="clang++"
CGO_ENABLED="1"

And this is what is look like in the /Users/Tom/Go

Thanks VonC, however, this doesn't work. I am not sure what's the reason.
This is the envionment setting using GOCODE

This is several steps!
step1

By the way, I noticed that there are a difference from mac and windows when creating a new Go Project
at this step, the windows platform will show a "project sdk" while mac won't.

Make sure your IntelliJ project reference the right path within GOPATH.
From the plugin page:

> If you have only one directory in the GOPATH and you are creating a project inside that path when you are working with packages that are part of the project you must still specify the whole import path for them, not the relative one. Example:

> - GOPATH is: /home/florin/go
the correct way to setup a project called demogo is: /home/florin/go/src/github.com/dlsniper/demogo/

• new package is: /home/florin/go/src/github.com/dlsniper/demogo/newpack
• the correct import statement is: github.com/dlsniper/demogo/newpack not newpack

Also make sure you have the latest version of the plugin, as issue 756 illustrates that IntelliJ IDEA 13 doesn't create the project directory structure on Mac OS X.

Finally, check if IDEA has correctly detected GOROOT and GOPATH:
See the page "Fix missing environment paths (Mac)".

The OP python adds in the comments:

> - If I have create a new Go project, this new feature is disabled.

• If I create a new Java Command line App, then I could right click and add new Go file.

Right-click on either the top-level project or on the src directory and then go to Mark Directory As > Sources Root. After this you will be able to access the enabled Go context menus.