Can't use 'View Break' on my section view

[Duncan Lithgow]

As the title says, I just can't break my section. When I do click on that z icon I instead just get the message "Turning off the crop region of the view removes all View Breaks, ..."

What could be wrong?

[Duncan Lithgow]

I found the problem, Properties > Extents > Crop view must be checked in order for the view split to work.