Hi Pat
I suggest to do that with an FieldEditor. Then you can conditionally render the field “Reason for Lost Opp” with:
Source Type: Model field value
Source Model: Opportunities
Field: Stage
Operator: =
Content: Single specified value
Value: Closed Lost

If your FieldEditor is in “Edit” Mode, the “Reason for Lost Opp” Field just will appear, when Stage is Closed Lost and is editable.

Yes, I don’t want the field editor to always be in edit mode.

what, when you build your Form by multiple FieldEditors, and render the whole editable Editor with just the given field in it? Ist that a possibility?

Certainly, I can use multiple field editors, but that require an odd placement for the field. I’d like it to display directly below the Stage field without having to create some silly series of components like a responsive grid or panel set.

This came up again for my Account Status field. When set to Churn, I would like to Churn_Date__c and Reason_for_Churn__c to be conditionally rendered in edit mode and required. The required part is there but not evident to the user unless they double click edit the fields.

I know internally we’ve discussed the notion of Field Level Modes, where it would be possible within the same field editor to have any permutation of Edit, Read, Inline modes on different fields. They would usurp the settings defined on the component level.

On that point we also tossed around the idea of Field Level Model Definitions where-by you could be editing many different models in the same field editor.