@end defun
@defun window-scroll-bar-width &optional window
-This function returns the width of @var{window}'s vertical scrollbar,
-in pixels. @var{window} must be a live window. If @var{window} is
-@code{nil} or omitted, it will be the selected window.
+This function returns the width in pixels of @var{window}'s vertical
+scrollbar. @var{window} must be a live window, and defaults to the
+selected window.
@end defun
If you don't specify these values for a window with