civicrm/civicrm-core — pull request #2036 by agh1 (2013-11-19 18:39:17+00:00)
Title: CRM-13800 Prevent people from enabling contribution amounts when there's a membership price set

If someone has a membership price set enabled on a contribution page, they still see the checkbox to enable the contribution amounts section. Checking that box displays an error on validation, but it's a cruel trick to let someone check something they won't be allowed to check.

I made a little change to hide and explain it if there's a membership price set in use.