Window Splitting Not Responding Correctly

[NecroTechno]

On one monitor, the vertical and horizontal split command has no effect, and on the other, the commands do not act accordingly, or after opening more than two windows, they overlap.

[syphoxy]

I've set this up as well and I can't seem to get any form of splitting working. it's just always horizontal. I can't tell if I didn't set this up properly or if it's broken.