Thank you for the provided example.
I forwarded your case to the corresponding staff members. The positioning that you observe is expected - by default the popup should align to the bottom left corner of the SplitButton wrapper, when there is not enough space the popup container will "fit" e.g. position itself in the visible part of the screen. In this case the popup will not
align with the bottom right corner of the container but move to the left as much as it is needed.
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI