I'm experiencing strange behaviour at runtime which I believe is inconsistent with design time. First picture shows design time view which is how I would like it to appear (almost anyway; last column needs to be extended to fill). The second picture shows runtime view. Initially there is a splitter bar across the top and the area below has no vertical scroll bar. I have dragged the splitter down revealing the same data with a vertical scroll bar. I only want to see the top area; not the lower area. Are these row scroll regions? If so, I've set it to 1 to try to prevent extra areas from appearing but why no scroll bar. I'm new to using the grid so any help appreciated. 

Thanks,

Craig

Design time:

 Run time: