diff --git a/runtime/doc/scroll.txt b/runtime/doc/scroll.txt
index 941e5bd..0126195 100644
--- a/runtime/doc/scroll.txt
+++ b/runtime/doc/scroll.txt
@@ -237,31 +237,34 @@
 |xterm-mouse-wheel|.  By default only vertical scroll wheels are supported,
 but some GUIs also support horizontal scroll wheels.
 
-For the Win32 GUI the scroll action is hard coded.  It works just like
-dragging the scrollbar of the current window.  How many lines are scrolled
-depends on your mouse driver.  If the scroll action causes input focus
-problems, see |intellimouse-wheel-problems|.
+On MS-Windows, if the scroll action causes input focus -problems, see
+|intellimouse-wheel-problems|.
 
-For the X11 GUIs (Motif and GTK) scrolling the wheel generates key
+For Win32 and the X11 GUIs (Motif and GTK) scrolling the wheel generates key
 presses <ScrollWheelUp>, <ScrollWheelDown>, <ScrollWheelLeft> and
 <ScrollWheelRight>.  For example, if you push the scroll wheel upwards a
 <ScrollWheelUp> key press is generated causing the window to scroll upwards
 (while the text is actually moving downwards).  The default action for these
 keys are:
-    <ScrollWheelUp>	    scroll three lines up	*<ScrollWheelUp>*
+    <ScrollWheelUp>	    scroll N lines up	        *<ScrollWheelUp>*
     <S-ScrollWheelUp>	    scroll one page up		*<S-ScrollWheelUp>*
     <C-ScrollWheelUp>	    scroll one page up		*<C-ScrollWheelUp>*
-    <ScrollWheelDown>	    scroll three lines down	*<ScrollWheelDown>*
+    <ScrollWheelDown>	    scroll N lines down	        *<ScrollWheelDown>*
     <S-ScrollWheelDown>	    scroll one page down	*<S-ScrollWheelDown>*
     <C-ScrollWheelDown>	    scroll one page down	*<C-ScrollWheelDown>*
-    <ScrollWheelLeft>	    scroll six columns left	*<ScrollWheelLeft>*
+    <ScrollWheelLeft>	    scroll N columns left	*<ScrollWheelLeft>*
     <S-ScrollWheelLeft>	    scroll one page left	*<S-ScrollWheelLeft>*
     <C-ScrollWheelLeft>	    scroll one page left	*<C-ScrollWheelLeft>*
-    <ScrollWheelRight>	    scroll six columns right	*<ScrollWheelRight>*
+    <ScrollWheelRight>	    scroll N columns right	*<ScrollWheelRight>*
     <S-ScrollWheelRight>    scroll one page right	*<S-ScrollWheelRight>*
     <C-ScrollWheelRight>    scroll one page right	*<C-ScrollWheelRight>*
 This should work in all modes, except when editing the command line.
 
+The value of N depends on the system.  By default Vim scrolls three lines when
+moving vertically, and six columns when moving horizontally.  On MS-Windows
+the amount of lines and columns for each scroll action is taken from the
+system-wide settings.
+
 Note that horizontal scrolling only works if 'nowrap' is set.  Also, unless
 the "h" flag in 'guioptions' is set, the cursor moves to the longest visible
 line if the cursor line is about to be scrolled off the screen (similarly to