Is it not possible to mark repos we do not use as "Hidden"?

For example, within the details section of each repository is this:

Base URL:$RCE/SLES11-SP3-Pool/sle-11-s390x/
Trusted_ Internal_ Hidden_
Additional options

Trusted and Internal are checked. I check Hidden, then click the "Save changes" button and the Hidden checkbox is unchecked. It never gets applied.

Or is the preferred method to simple click the "Delete" button at the bottom?