Recently, in our company we moved from Bitbucket to GitLab. In Jira Development Panel we can see commits, branches and pull requests, but we cannot create branch directly from Jira issue to GitLab. When we were using Bitbucket, this option was available.
So, I've just installed Jira Data Center and GitLab testing versions to see if it is possible to create branch directly from Jira to GitLab, and I have a problem. Jira <--> GitLab integration was done correctly, because the repositories were synchronized, and I can check commits in Jira issue, but still can't create a new branch.
Jira/Bitbucket integration:

Jira/GitLab integration:

I have used DVCS Connector to integrate Jira and GitLab.
Both Jira and GitLab on production are self-managed.