Hi 3image, I have one over here that doesn't behave like that.

Does it behave odd with just one particular model? What happens if you use it on a totally blank MoI that you just start up?

You might try changing the 3D view to a parallel projection instead of the default perspective. You can do that under Options > View > "3D view projection". Zooming in a perspective view can be awkward due to the non-linear nature of perspective foreshortening.

If a parallel view is more controllable for you, you can make the default on initial start up by saving a .3dm file with it set as parallel and then using that as the startup template file under Options > General > "Template file".

- Michael