On the Service_Request Layout , the lookup field "Quote" is the controlling field. If a Quote  is selected, I can see the Products related to the selected Quote.
That means, if I re-select the Quote, I can see the Products related to the new selected Quote and can choose one of them.

How can I implement this logic ?

Hi

I am fairly new to Force.com development and have hit an issue trying to build some relationships on a custom object.

I have an 'Assessment' custom object with a custom lookup field to a 'Claim' custom object.  I want to build a further custom lookup field on Assessment: 'Claim Contact' that looks up from another custom object, but this object is the detail in a master-detail relationship with the Claim object. 

I want to know how to constrain the 'Claim Contact' lookup so that it only shows values that are related to the Claim that has already been looked up on to the Assessment.

i.e. if the Assessment is linked to Claim A, which has child Contacts Jack and Jill, then these should be the only contacts I am able to pick using the 'Claim Contact' lookup on the Assessment.  If the assessment is not linked to any Claim then I need the lookup to return no results.

Is there a configuration solution to this or if not does anyone know what the best approach is to do this?

Many thanks in advance!