Grouped pipeline dropdown should be a scrollable container
Currently the grouped pipelines dropdown has no height contraints, this isn't too bad for gitlab-ce but I've seen some projects with crazy CI configurations.
I suggest we make the pipeline dropdown a scrollable container with a sensible max-height property, around 250px?
It may be wise to wait for !6347 (closed) and use this as the pipelines graph is also in a fluid container.
I also think UX should look into finding a paradigm to show a dropdown box as 'scrollable', I noticed whilst creating !6347 (closed) that it may not be immediately obvious to users that the box that just popped up has more items within when scrolled.