Use all dynamic and free fields when merging tickets.
We use Dynamic fields and Free fields to map tickets to products or orders.
However when we merge a ticket that doesn't have any free/dynamic fields we
need to be certain to merge it in a specific order otherwise the free/dynamic
fields will be removed/emptied.
Better would be to map the fields of both tickets. If one ticket doesn't have
the free/dynamic field, use the one of the ticket that does have the info. If
both tickets have info, use the current implementation.
loop over all dynamic/free fields for ticket #1
if length of field ticket #1 > 0 and length of field ticket #2 = 0
then use field of ticket #1
else use field of ticket #2
If this is undesired, you could also make a setting for it so it can be