Create a dependant field in QC Defects
How do I create a relationship between a default status and a user field?
When I select the Fixed status the user field must be enabled to fill. This user field is required and can only require completion when it is enabled.
Go to Project Customization --> Workflow --> Script Generator - List Customization for Defects Module.
You can specify which primary field value change should reflect on which secondary(dependent field) field values. UI have limited option only here, but you can achieve your requirement via code.
These links will give you some ideas on how to achieve.
All the thoughts here are mine not related to my employer nor anyone.
Test Automation Ecstasy