Is there any way to override the way organization lookup control matches to rather use "contains" instead of "startswith" and sort by Title rather than Created?
Change Organization lookup control to use "contains" instead of "startswith" when finding matches?
Thank you for your question. HelpDesk uses Cross-site lookup internally for this lookup column. It is another of our products.
You need to install Cross-site lookup and follow this article to change filtration of the lookup.
Note: the product is not included in HelpDesk license. You will need to buy it separately to allow customizations.