, please read above. (Your post was moved by me to this topic.)
You are right regarding to the links to the power tip about vertical and horizontal splitting of workspace for comparing two (or more) files manually. The linked power tip page is currently not available.
I don't know the plans of IDM Computer Solutions, Inc. regarding this feature. I suggest to report the issue by email to IDM support. The more users report this issue by email, the higher becomes the priority for fixing or re-implementing this feature.
Edit: The power tip Vertical & Horizontal Split Window
was made available again after this feature became available again in UltraEdit and UEStudio.