Idea Summary
When a column is Read Only, you can control if you can enter the cell with the tab key using skipReadonlyCells

However, there are cases where the read only column has to be part of the submit. The usual solution is to set the CSS class of the column to apex_disabled, which prevents clicking on and editing the item.

Adding tabindex="-1" doesn't work for IGs, so you can still use the Tab key to edit the cell.

Idea: IGs should also skip cells that have class apex_disabled.

Note: class is-readonly instead of apex_disabled seems to do the trick, but for consistency I think apex_disabled has a more common use.

Use Case
Calculated read only cells that should be part of the submit. E.g. end_date = start_date + 7.

Preferred Solution (Optional)

Something like this in widget.grid.js?

            nextCell$ = next( cell$ );
            if ( skip ) {
                while ( nextCell$.hasClass( C_READONLY ) ) {
                    nextCell$ = next( nextCell$ );
                }
            }
            return nextCell$;
            
            Change it to:
            
            nextCell$.hasClass( C_READONLY ) || nextCell$.hasClass( C_APEX_DISABLED )