For example:
I have 1 Custom field browser (list) that have some values in it (Chrome, Firefox Safari etc.)
I set that custom field on the screen:
- Test
- Instance
- Issue

When I Create new Test and I set the Browser: Firefox when im done with the Test --> Il Create TestSet & Instance = When im in the instance screen I see the Custom field Browser thats already filled in with 'Firefox' that I have selected in the screen Test.

Start the instance and there is a Issue --> Create an Issue, Open the Issue screen and there is the custom field Browser also thats already filled in with 'Firefox'

Value of the custom field Browser thats connected with the Test. comes back in the Instance & Issue screens. And have selected 1 time.

That was my Idea. But its not only for list, i was also thinkg for number fields.