CPQ Redwood: Freeze LIG columns to help with scrolling on Large Quotes

When a LIG contains a large number of line items, users must scroll both horizontally and vertically to review data. Introduce the ability to freeze selected LIG columns so they remain visible while scrolling, improving usability, navigation, and data comparison across line items.

Use Case:
Users managing quotes with hundreds of line items need key columns (e.g., Line Number, Product Name, Part Number) to remain visible while scrolling through the LIG.