Confusing linked batch input in tool form

[mvdbeek]

Reported on gitter by @TorHou
"I have this problem with bowtie2. I can neither select one or two reference genome fasta files, it wants four because I have four files to map."

Selecting a single reference works, but the necessity to have an equal number of reference genomes is a bit confusing here.

[jmchilton]

For sure - I can't find an existing issue for this - maybe I could hunt it down in Trello - but the backend allows both cross products and dot products and this needs to be clear and configurable from the front end. I'm linking to this issue from #4707 since this is one of the easiest wins we could do for the data input selectors since the backend already allows this.

This GUI was added for workflows along time ago (https://bitbucket.org/galaxy/galaxy-central/pull-requests/75/enhanced-batch-workflow-mode/diff) I'm not sure if it is still there though.

[hexylena]

I think we have a new UI for this in dev? Is this then resolved?