This exists in Cubase, both horizontal crosshair and vertical. It would be even more significantly useful in Spectralayers and make removing sounds that repeat (click click bleed) much quicker and easier on eye/brain/hand coordination.
this feature along with showing the frequency location next to the cursor as well as time, all separate options to turn off/on. would be fantastic thanks.
Definitely allow the width of the crosshair to be user adjustable (like in Cubase) as I would make mine as thin as possible (1px). An authentic idea could be having the crosshair gradually disappear at the very center so as to not obscure the spectrogram data at the utmost center of the cursor.