Anyone know if smooth scrolling can be disabled in the new version 4?

Not yet.

This issue has been added to the tracker:
Issue 128 – Optionally disable smooth scrolling in an internal editor

Someone else appears to be having the same issue:
Disable smooth scrolling in text editor

Anyone know if smooth scrolling can be disabled in the new version 4?

Yes, if it is possible to offer the option to disable smooth scrolling, I'm sure many would appreciate it. Otherwise, great prog.

It cannot be turned off. Maybe in the next version.

How do I turn it off?

This is occuring when scrolling with the mouse scroll wheel. Thankfully it doesn't do "smooth scrolling" when navigating the document using PgUp/PgDn.

How do I turn it off? Smooth scrolling annoys the crap out of me.