I've choosen a Git-Workflow, with master, develop and feature branches like this:

I'm working with the Bitbucket Webinterface!
I've created a develop branch from the master branch like this:

Now I'm trying to create a feature branch from the develop branch like this:

As I open the created feature branch, it shows following:

Shouldn't the destination be develop, as I set it up?
If I change the destination to develop and reopen the site, the destination is changed back to master .... Why?
If a feature is finished, I want to merge it to the develop branch and not to the master branch.