Moving an issue from one sprint to another should intelligently replace Fix Versions, not wipe them out completely

We use Fix Versions as a multiple select field. If we commit a fix to some common code that is used in an upcoming release for siteA.com and siteB.com we want this issue to have Fix Versions siteA.com Release 23 and siteB.com Release 58 for example. If I for some reason move this issue from siteB.com Release 58 -> siteB.com Release 59, GreenHopper wipes out the siteA.com Release 23 Fix Version I had set.

GH should look at where you're moving from when determining how to update the Fix Version field. If moving issue from siteB.com Release 58 -> siteB.com Release 59, remove the siteB.com Release 58 Fix Version and add the siteB.com Release 59 Fix Version, don't wipe all of them and reset it.

This is the main blocker for us and is why we didn't purchase GreenHopper but rather just using what JIRA offers.