A nice and useful feature would be to have the possibility to enter a marker in a Cartesian plot and define (with keyboard) the desired x-value. Indeed, doing this way is much faster than continuously pressing the right/left arrows or desperately trying to catch the right curve and the right x-value with the mouse.
yes, I think we discussed this on GitHub some time ago and were about to add it but the markers code was/is in the middle of a refactoring. Unfortunately nobody seems to have time to work on the code currently.
I often just delete a marker and place a new one when I need to move it fast... surely not the best solution.