[Gmsh] How can i zoom in the work window ?

[philippe carette]

I am building some mesh.
And the more objects i add (points, lines, etc...), the more little 
becomes the window visualizing the model.
Is there some tip to zoom on a part of the model ?

Another question, (and perhaps a similar problem with the upwards 
visibility question) :
i built a sphere, using the tutorial 5's method of the CheeseHole 
function (copy and paste in the edit.File of the project).

When i do Tools->visibility, the points and circles built with this tip 
don't appear in the list.

What is wrong ?

Tx for your help.