If we can use the weighted ttk paned window, so sash movement is only used when really needed (small windows) then it would be ok. (I would add a note in one of the help texts -- "On some systems, there are visual artifacts when enlarging the window or moving the sash. We feel this is preferable to having to scroll a too narrow text window.") There is some stuttering when enlarging the window, but if only done once, it is not a big deal.