Setting the extend last system checkbox seems to extend only the last bar. However, if you instead use the section close barline with the Force system break checkbox, you get a much more aesthetically pleasing staff, but must then manually edit out the last system. Is there any way to fix this?
Just add a bar line at the end of your last bar, and make it a forced system break. The staff won't wrap to the next line if there is no notation or text between this "unnecessary" bar line and the end of the staff.
(I generally use forced system breaks a few times near the end of the chart, just so there is a more gradual reduction in the number of bars per staff at the end. - i.e. if there are 100 bars, I'd probably have forced system breaks at the end of bars 100, 96, 90. 84 if that looked "right.")
Useful trick! *And, aye, you kind of have to use forced system breaks - otherwise, nine times out of ten, it seems, you end up with a single bar in the last system. Not to mention the whole problem of breaks at the end of a page in the middle of fast complicated passages.
I'm pretty sure I can remember a time when we didn't have forced system breaks. Very handy.
This FAQ includes a tip for the last system:
FAQ - Is there a line break command?
http://ntworthy.com/composer/faq/33.htm
I can add that while you add the last decorated bar line, make sure it is of the type "Section Close", or otherwise the score will look funny, ending in a single bar line. Most people probably already figured out this, but it is worth mentioning. Of course you could make the last bar line any type you wish, but in most cases it should either be a Section Close or perhaps Master Repeat Close.