Can I disable this feature? I keep accidentally expanding my canvas but I need my canvas to be a set size.

From what I understand it's a very old feature, but I don't seem to see anyway to adjust it or turn it off.

http://dimula73.blogspot.com/2013/05/krita-28-prealpha-new-pseudo-infinite.html

No, there is no option for that. I wonder how anyone can keep accidentally pressing those buttons, I usually have to explicitly scroll the canvas view to reach them.