When enabling keep_tasks, the existing properties of a category (i.e. Incident/ Request area) are hard coded to stay at the top of the properties tab. If the category is changed, the new properties are populated below the existing properties. If the line limit is exceeded, some of the new properties will not be accessible. If any of the new properties are required that cannot be accessed, you are not able to save the ticket. I propose the order be switched. New properties should be populated at the top and existing properties moved below, that way if the line limit is exceeded, there are not any issues and all needed data can be collected.