Attributes from related objects are not being displayed on the window. I.e On Incident window when selecting Category, should then display the Category.script attribute which is on the window as a read-only related attribute. Handler issue.
On the attribute which selects the object i.e. Category or Raise User, you need to add the handler UpdateRelatedFields on event ValueChanged.
In Window Manager, select the window to modify select the attribute i.e. Category and select the properties icon. Select Handlers property and display Handlers window. In Available Handlers under RelatedFieldHandler, add the handler UpdateRelatedFields on event ValueChanged to the configured handlers.
Click OK and save changes to the window.