Salesforce Lightning Modal Fix — Opportunity Information Duplication

Overview

When creating a new Opportunity in Salesforce Lightning, the "Opportunity Information" section can appear duplicated in the modal — the same fields rendered twice, once at the top and again below. This is a known Lightning behavior, not a data or layout bug, and requires a specific fix at the Quick Action level.

Client context: First encountered on the Quarra Salesforce instance during a working session with ^[1].

Root Cause

Lightning's modal rendering logic pulls in every page layout section that contains a required field. If a required field (e.g., a custom field like Process_C or Loss_Reason) lives in a section that is not explicitly included in the Quick Action's field list, Lightning will import the entire parent section to surface that required field — causing the section to appear twice.

"Lightning pulls the entire operating section to show those required fields."
— AI agent diagnosis during working session

In the Quarra case, the "New Opportunity" Quick Action was missing required fields (Process_C, Loss_Reason) that existed on the full page layout. Lightning compensated by pulling the entire "Opportunity Information" section, duplicating it alongside the Quick Action's own fields.

Resolution

Add the missing required fields directly to the Quick Action so Lightning no longer needs to pull them in from the full page layout.

Steps

Go to Setup → Object Manager → Opportunity → Quick Actions
Open the New Opportunity Quick Action
Add all required fields that are not already present on the Quick Action layout — specifically any custom required fields (e.g., Process_C, Loss_Reason__c)
Save the Quick Action
Hard-refresh the browser (Ctrl+Shift+R) and test by clicking New on the Opportunity object

Expected Result

With all required fields present on the Quick Action itself, Lightning no longer needs to import additional sections from the full page layout, and the duplication disappears.

Caveats

Caching: The fix may not be immediately visible after saving. Always perform a hard refresh (Ctrl+Shift+R) before concluding the fix didn't work.
Multiple record types: If the org uses multiple Opportunity record types, each may have its own Quick Action or page layout assignment. Verify which Quick Action is active for each record type via Lightning App Builder → Record Page → Activation.
Heavily customized instances: In orgs with significant prior customization, conflicting triggers or layout overrides can obscure whether a fix has taken effect. Test in a clean browser session or incognito window if uncertain.

General Principle

This pattern applies beyond Opportunities. Any Lightning modal that shows a duplicated section is almost certainly caused by a required field missing from the Quick Action. The fix is always the same: add the missing required fields to the Quick Action layout directly.

Objects where this commonly surfaces:
- Opportunity (New Opportunity quick action)
- Case (New Case quick action)
- Custom objects with required fields added after initial setup

^[2]
^[3]