Lookup select box performing slowly after upgrade to Kingston from Helsinki
Most Probable Cause
The Lookup select box is an ideal choice only when the number of choices is very limited (~20). When there are hundreds of active records, even after the reference qualifier is applied, it results in too many choice options in the lookup select box, considering that the choices vary based on other options chosen on the form.
In such a scenario, the Lookup select box is not a suggested option, since the end user has to manually go through a large number of available choices to pick the right one. On the other hand, a reference variable has the convenience of auto-suggest which makes it a convenient option. As per the design, it is not suggested for tables where the data is not constant and might increase.
The Lookup select box is performance intensive when the number of choices is large and a reference variable is better performant at handling such data.
In Kingston, the Service Catalog form was refactored under the hood to improve design and performance. Adding the true/false property glide.sc.use_sc_form_v2 and putting the value as false should workaround the issue by using the pre-Kingston catalog form.