Set Let Categories Determine Assignees to “Yes” when categorization fields change.
Necessary to have the auto-assignment rules run after the incident is created or updated.
Adding a fixed amount of delay before the code runs might work most of the time but inexplicably fail other times.
Instead, the more flexible Auto Field feature must be used.
The potential problem with Auto Field is that it runs each and every time an incident is updated and we don’t want the assignees to change if they’ve been set by other means throughout the incident’s lifecycle.
I prefer to drop it into the area above the tabbed sections so that it will always be prominent when viewing the Form Designer.
You should be aware that while the Custom HTML element we are going to add is not going to contain any visible content, it will still occupy a space on the form’s layout grid.
That’s it for the step-by-step portion of this tutorial.
What remains is to create and populate the Category and Sub Category fields, and to create some Auto Field rules that set the assignees field based on combinations of these two fields plus the Allow Categories to Determine Assignees (having a value of “Yes” in each rule).
The Form Designer does not allow fields to be placed in this section, establishing the case for a Java Script customization.
While this particular use case may not be of any interest to your organization, by following this tutorial, you will receive advice on best practices and find code that can be reused in your own customizations.