Problems with red-letter highlighting

[Enyium]

Problems I encountered with the highlighting red letters of the frame grid:

• When I choose row a, all horizontal alphabets of all boxes are highlighted. This distracts from the actual row that I said to the software I'm interested in and requires me to orient myself by the subtle difference in number box background colors and the lack of a number.
• When I choose a row other than a, it's okay that the same row in other number boxes is subtly highlighted (by not adding letter labels, but only coloring a single one red), but I think the letter labels of the other number boxes shouldn't change their label to "a", because there's no horizontal navigation required as the next step.
  • Also, it may be better if the number box to the right of the current number box wouldn't get its row highlighted, so that you don't have a red letter label right next to the complete horizontal alphabet of the current number box as a kind of continuation of the alphabet that won't react though.