A simple workaround would be to put a Label control in the desired position and bind it to the maximum y-value.
Is your vertical axis a LinearAxis, and are you using a CategoryAxis for the horizontal axis?
I have only LinearAxis in the chart.. for the vertical and the horizontal one.
Thanks but.. i can't see the way to solve, this way... if i have, on the vertical axis, the labels 0, 100, 200, 300, 400.. and i start dragging.. when i have the max value for that axis = 460, for example.. i go on seing only the labes 100, 200, 300, 400.. and in the label funcion i only get this four values.. i'd like, in this case, to show 460 too.. i mean, i'd like to show always the max value of the axis (and the minimum one).. i think this way i should solve..)..
I can see that setting a lower "interval" value on the LinearAxis help a bit.. but this is not the way i want to solve the problem.