The figure below shows the Miscellaneous section of the World Editor:
There is only one category, Scrolling, which controls the behavious of the scrollback buffer.
Scroll on output, when checked, will cause the buffer to always scroll the end when new text is received, thus displaying it immediately. If not checked, the buffer is only scrolled if you are at the end.
Lines to save in scrollback buffer determines how many lines of output will be saved in the buffer for you to see again. Note that KildClient will get slower and will consume more memory if you set this to too high a number.