Thought I'd post this here in case anyone else has this issue.
I've been going nuts in Dynamo 2 because every time I tried to Pan around my graph, Dynamo would zoom out and my graph would end up as a little dot.
After a few months attempting to deal with it, I finally figured out the root cause.

I have a Logitech M510 mouse.
The wheel is one of those "tilty" wheels. It not only scrolls by spinning the wheel, but you can click down on the wheel.
AND you can tilt the wheel to the left or the right.
The "Tilt left" and "Tilt right" functions in the mouse driver were set to Zoom.
So when I thought I was panning by holding the wheel down, I was actually tilting it to one side and Zooming.

I used the Logitech configuration options to set the left and right tilt options to "None" and now I'm happily panning around without tearing my hair out!