How to add a 'marker' and a 'textbox' for a given x,y,z in a surface?

Hi guys,

A relatively simple question. I want to graph the below surface. But with it, I want to highlight just ONE point based on a given x,y (in this case f1, f2) and have a related textbox appear which gives me the coordinates. For example, like this:

*X-Value: 4 Y-value:5 Z-value: 2

I tried data cursor, but it requires that you click on it and it doesn't become PART OF the surface.

Thank you. Here is the test surface:

x = [0:20];
y = [0:20];

f1 = 1;
f2 = 2;
constant = 3;

% Calculate data
TestFormula = @(x,y)(x + y.*constant);
[X,Y] = meshgrid(x,y);
Z1 = TestFormula(X,Y);
Z2 = TestFormula(f1,f2);

% Create frequency plot in proper axes
s1 = surf(X,Y,Z1);
xlabel('X', 'fontweight', 'bold')
ylabel('Y', 'fontweight', 'bold')
view (135,15);
yh = get(gca,'YLabel'); % Handle of the y label
set(yh, 'Units', 'Normalized')
pos = get(yh, 'Position');
set(yh, 'Position',pos.*[0.85,0.6,1],'Rotation',-10.9)
xh = get(gca,'XLabel'); % Handle of the x label
set(xh, 'Units', 'Normalized')
pos = get(xh, 'Position');
set(xh, 'Position',pos.*[1,1,1],'Rotation',11.1)
zlabel('Z', 'fontweight', 'bold')
zh = get(gca,'ZLabel'); % Handle of the z label
set(zh, 'Units', 'Normalized')
pos = get(zh, 'Position');
set(zh, 'Position',pos.*[1.5,1,0],'Rotation',90)
axis tight
camlight
lighting phong
shading interp
set(s1,'FaceColor',[0 0.63 0.91], 'edgecolor',[0 0 0.4],'meshstyle','both','linewidth',.15);
grid on

[Walter Roberson]

is this question solved by http://uk.mathworks.com/matlabcentral/answers/221724-how-to-add-a-marker-and-a-textbox-for-a-given-x-y-z-in-a-surface ?