Q:

Using external Git Repo in VSO not fully working

I try to use an external Git Repository which is hosted in GitHub (Private repository) in Visual Studio Online. I followed the official documentation to add a Service. 
I tried both using the GitHub service, but also the "External Git" - Service. Both have the same behaviour.
After creating the Service, my Code can be seen in the "Code"-Tab. But the issue is: I only can see the MASTER-Branch. All other branches are NOT available under "All Branches".
In addition I do not seem to get any updates (even in the master). VSO seems to have a snapshot from the time I created the service but never gets an update.
What could be the issue here?

A:

VSTS team project Code Tab only shows the repositories hosted on VSTS itself, not any external git repo (github, bitbucket etc).
So what you see on the Code tab should be the git repo hosted on VSTS not Github. You can double check by clicking clone (on the top right corner of the Code Tab), you will find the remote repo URL is hosted on VSTS not github.

The Github service Endpoint is mainly used for building projects which hosted on github, and you can select your github repo and related branches in VSTS build definitions.

