There are several scenarios where an Incident triggers a Service Request. For example, "computer cannot boot" incident which leads to the service request for "new laptop". From the Incident, we are unable to add the Service Request as a linked/child item. It seems that if the original ticket is an incident, only incidents can be add with the same true for service requests.
How is everyone else handling these type of tickets?
I too see that the option to 'add item' from within the incident ticket is not available. What I currently do is 'Merge' the ticket with an already created SR. In your case, you would simply create the SR for 'new laptop' and then merge the two. If there's another way to do this I'm all ears!
As a feature request, I would like to see this added as an option. When viewing, for instance an 'Incident' ticket, the 'Associate' menu in the upper right corner should have an option for 'Service Request' as well. There's options for Problems, Changes and Projects, but not Service Requests?