Navigation Order in Root Expression

Dear @NSoiffer
We are customizing to have MathCAT read elements in a math expression while editing with a math editor.
We have an issue of navigation order between MathCAT and the editor for root like this: in navigation mode and moving to the right, MathCAT moves to read the content of the root first, then will be the root index like cube or fourth or square root. While, our math editor moves to the root index first, then will move to the root content.
May I know if we could make MathCAT to move to and speak the root index before to the root content when using right arrow?
This will help it speak correctly rather than in reversed wrong value.
Many thanks.