How to edit Junk Email Filter Blocked Domains

Question

How do you edit Junk Email Filter Blocked Domains?  I go to the Junk email filter manager, select Block Domain and select Edit.  It then opens a window that says Block Domain for the Rule Name: and there is a Filter by &quot;From&quot; contains ( ...   and I think all my selected domains to block are there, however, I can't actually change, add or delete the domains shown there.  How do I modify the list?