Grand Totals field in MUX editable, but values do not save

Products

• Clarity PPM On Premise
• Clarity PPM SaaS

Issue/Introduction

On the Modern UX the Grant Totals field is editable, but no changes are saved as it always reverts to the previous value. If no changes are allowed the field should be read-only.

STEPS TO REPRODUCE:  
1. Admin > Studio > Objects
2. Create a subobject of the project object and enable it for MOUX
3. Create a Money type Time Varying attribute
4. Add the subobject as a module to a blueprint
5. Go to a project and subobject module
6. Create a subobject instance
7. Open the View Options menu on the grid
8. On the Per-Period Metrics add the custom time-varying field
   Use the Sum of Periods as Totals
   Add the Total filed column to the grid
9. Add some values over the periods
10 Notice the Total value is calculated as you enter values on the individual cells.
11. Update the Totals field and notice the changes are spread over the periods.
12. View Options > Select Grand Totals as Total
13. Update the Total value. Notice the value reverts back

Expected Results: As direct updates to the Grand Totals are not meant to be done, the field should be read-only
Actual results: The field is editable but no changes are allowed  

Cause

This is caused by DE66043

Resolution

From 16.1.0 onwards the following Toast message will show:

"To enter a new total amount, use Sum of Periods Totals view option" 

This will pop up when there is a null curve (no curve means no date boundaries exist) and the Totals View Option is set to 'Grand Totals'