bug#998: after split-window-horizontally scroll works only on first window

[martin rudalics]

> it does fix the problem!

OK.  So I could install the attached patch.  Any objections?

martin

*** scroll-bar.el.~1.59.~       2008-05-06 09:57:49.000000000 +0200
--- scroll-bar.el       2008-09-30 08:56:36.312500000 +0200
***************
*** 295,300 ****
--- 295,311 ----
  
  
  ;;; Tookit scroll bars.
+ (defcustom scroll-bar-resample-mouse-position nil
+     "Non-nil means re-sample mouse position when scrolling.
+ When your mouse-wheel scrolls the wrong window, setting this to
+ non-nil might help.  The mouse cursor must be within the window
+ you want to scroll in order for this to take effect.
+ 
+ This option works for toolkit scrollbars only."
+     :type 'boolean
+     :group 'frames
+     :group 'mouse
+     :version "23.1")
  
  (defun scroll-bar-toolkit-scroll (event)
    (interactive "e")
***************
*** 302,341 ****
         (window (nth 0 end-position))
         (part (nth 4 end-position))
         before-scroll)
!     (cond ((eq part 'end-scroll))
!         (t
!          (with-current-buffer (window-buffer window)
!            (setq before-scroll point-before-scroll))
!          (save-selected-window
!            (select-window window)
!            (setq before-scroll (or before-scroll (point)))
!            (cond ((eq part 'above-handle)
!                   (scroll-up '-))
!                  ((eq part 'below-handle)
!                   (scroll-up nil))
!                  ((eq part 'ratio)
!                   (let* ((portion-whole (nth 2 end-position))
!                          (lines (scroll-bar-scale portion-whole
!                                                   (1- (window-height)))))
!                     (scroll-up (cond ((not (zerop lines)) lines)
!                                      ((< (car portion-whole) 0) -1)
!                                      (t 1)))))
!                  ((eq part 'up)
!                   (scroll-up -1))
!                  ((eq part 'down)
!                   (scroll-up 1))
!                  ((eq part 'top)
!                   (set-window-start window (point-min)))
!                  ((eq part 'bottom)
!                   (goto-char (point-max))
!                   (recenter))
!                  ((eq part 'handle)
!                   (scroll-bar-drag-1 event))))
!          (sit-for 0)
!          (with-current-buffer (window-buffer window)
!            (setq point-before-scroll before-scroll))))))
! 
! 
  
  ;;;; Bindings.
  
--- 313,361 ----
         (window (nth 0 end-position))
         (part (nth 4 end-position))
         before-scroll)
!     (when scroll-bar-resample-mouse-position
!       ;; With some mouse drivers the window reported in EVENT might not
!       ;; be valid, see Bug#998.  Here we re-sample the mouse position in
!       ;; the hope to get a more suitable window.
!       (condition-case nil
!         (let* ((mouse-position (mouse-position))
!                (mouse-window
!                 (window-at (cadr mouse-position)
!                            (cddr mouse-position)
!                            (car mouse-position))))
!           (when (window-live-p mouse-window)
!             (setq window mouse-window)))
!       (error nil)))
! 
!     (unless (eq part 'end-scroll)
!       (with-selected-window window
!       (setq before-scroll (or point-before-scroll (point)))
!       (cond
!        ((eq part 'above-handle)
!         (scroll-up '-))
!        ((eq part 'below-handle)
!         (scroll-up nil))
!        ((eq part 'ratio)
!         (let* ((portion-whole (nth 2 end-position))
!                (lines (scroll-bar-scale portion-whole
!                                         (1- (window-height)))))
!           (scroll-up (cond ((not (zerop lines)) lines)
!                            ((< (car portion-whole) 0) -1)
!                            (t 1)))))
!        ((eq part 'up)
!         (scroll-up -1))
!        ((eq part 'down)
!         (scroll-up 1))
!        ((eq part 'top)
!         (set-window-start window (point-min)))
!        ((eq part 'bottom)
!         (goto-char (point-max))
!         (recenter))
!        ((eq part 'handle)
!         (scroll-bar-drag-1 event))))
!       (sit-for 0)
!       (with-current-buffer (window-buffer window)
!       (setq point-before-scroll before-scroll)))))
  
  ;;;; Bindings.