waterfall appear to be out of box

Hi everyone,

One waterfall plot appears that the curve are for outside the axis range. See this... Does anyone know how to fix this? Thanks!

Code 1 works without adjusting z axis range:

[x,y] = meshgrid(-3:0.1:3,10:30);

z = exp(-x.^2/5^2);

figure;
waterfall(x,y,z);

Code 2 doesn't work when I adjust the z axis [x,y] = meshgrid(-3:0.1:3,10:30);

z = exp(-x.^2/5^2);

figure;
waterfall(x,y,z);
set(gca, 'zlim', [0.8 1]);

see attached picture. Thanks!

[Yuji Zhang]