After working for a while I can no longer reliably pan in the network with the middle mouse button. It either doesn't work at all or it is intermittent and “sticky” until a restart of Houdini and then it goes back to normal. 17.5.350. I don't know if it's a bug or not but it sure is frustrating.

edit:It does it in the viewport too.

edit 2: I updated my Nvidia drivers and it works as expected now.

edit 3: I spoke too soon, it came back.