Bulk Edit for "Change Fix Version/s" multi-select field is addiditive, but replacement semantics is needed.

When we attempt to perform a bulk edit on several tasks to "Change the Fix Version/s", the behavior is that the field values provided in the bulk edit are additive – meaning that the values just get added to the existing values in the multi-selector for the "Fix Version/s" field and we can't get the old values removed. Is this expected behavior? If so, this is a problem when we have a number of cases that we planned to fix for one version and need to bulk change them to fix for a different version.

Ideally, there should be a "retain original values" checkbox to allow the semantics to be either additive or replacement.

Thanks, Irwin