Some of us have quite extensive outlines... and sometimes scrolling through them is time consuming and sometimes frustrating if one is dragging items around and inadvertentlly release the mouse button in an unexpected place.

It would be great to be able to split any outline pane into 2 horizontal windows (basically a little horizontal line in the middle of the pane). Something similar to Excel split window and/or freeze panes.

I know that the same effect can be achieved adding more panes, but there is a limit to how much horizontal space is there available for so many panes to be workable. Splitting the outline pane would immediately allow to fit 6 different areas of the outline instead of just 3 in the same screen real estate.

Another choice would be to extend the appliction window or the browser window across multiple monitors, but I think that is overkill and many people work from their laptops, so that should not really be an option.