Fixed this bug:

Fixed this bug:

** Mouse-face overlay bleeds into header line

From: Stephen Berman <Stephen.Berman@gmx.net>
Date: Thu, 21 Oct 2004 18:11:01 +0200

Mouse-face overlays bleed into the header line when the beginning of
the overlay is above (point-min).  To reproduce:

1. Start Emacs with -q -no-site-file.

2. In *scratch* eval

(progn (setq ov (make-overlay 66 92))
       (overlay-put ov 'mouse-face 'highlight)
       (setq header-line-format "test"))

3. Drag the mouse over the string "evaluation.\n;; If you want" and
notice the highlighting of only this string.

4. Now click on the down arrow in the scroll bar until the line
beginning ";; If you want" is directly below the header line.

5. Drag the mouse over ";; If you want" and notice that not only it
but also the header line are highlighted.