diff -r -u gtk+2.0-2.18.0.orig/gtk/gtkrange.c gtk+2.0-2.18.0/gtk/gtkrange.c
--- gtk+2.0-2.18.0.orig/gtk/gtkrange.c	2009-09-29 18:02:13.248054618 +0200
+++ gtk+2.0-2.18.0/gtk/gtkrange.c	2009-09-29 17:59:32.036061612 +0200
@@ -89,6 +89,10 @@
    */
   GdkRectangle trough;
   GdkRectangle slider;
+  /* slider size extended to the trough edge, 
+   * used for mouse event detection to fix Fitts' law problems with trough-border
+   */
+  GdkRectangle sliderMouse;
 
   /* Layout-related state */
   
@@ -2839,7 +2843,7 @@
     range->layout->mouse_location = MOUSE_STEPPER_C;
   else if (POINT_IN_RECT (x, y, range->layout->stepper_d))
     range->layout->mouse_location = MOUSE_STEPPER_D;
-  else if (POINT_IN_RECT (x, y, range->layout->slider))
+  else if (POINT_IN_RECT (x, y, range->layout->sliderMouse))
     range->layout->mouse_location = MOUSE_SLIDER;
   else if (POINT_IN_RECT (x, y, range->layout->trough))
     range->layout->mouse_location = MOUSE_TROUGH;
@@ -3188,7 +3192,9 @@
        * and the size/position based on the adjustment or fixed, depending.
        */
       layout->slider.x = layout->trough.x + focus_width + trough_border;
+      layout->sliderMouse.x = layout->trough.x + focus_width;
       layout->slider.width = layout->trough.width - (focus_width + trough_border) * 2;
+      layout->sliderMouse.width = layout->trough.width - (focus_width) * 2;
 
       /* Compute slider position/length */
       {
@@ -3231,7 +3237,9 @@
           y = bottom - (y - top + height);
         
         layout->slider.y = y;
+        layout->sliderMouse.y = y;
         layout->slider.height = height;
+        layout->sliderMouse.height = height;
 
         /* These are publically exported */
         range->slider_start = layout->slider.y;
@@ -3337,7 +3345,9 @@
        * and the size/position based on the adjustment or fixed, depending.
        */
       layout->slider.y = layout->trough.y + focus_width + trough_border;
+      layout->sliderMouse.y = layout->trough.y + focus_width;
       layout->slider.height = layout->trough.height - (focus_width + trough_border) * 2;
+      layout->sliderMouse.height = layout->trough.height - (focus_width) * 2;
 
       /* Compute slider position/length */
       {
@@ -3380,7 +3390,9 @@
           x = right - (x - left + width);
         
         layout->slider.x = x;
+        layout->sliderMouse.x = x;
         layout->slider.width = width;
+        layout->sliderMouse.width = width;
 
         /* These are publically exported */
         range->slider_start = layout->slider.x;
@@ -3441,7 +3453,7 @@
     case MOUSE_TROUGH:
       return &range->layout->trough;
     case MOUSE_SLIDER:
-      return &range->layout->slider;
+      return &range->layout->sliderMouse;
     case MOUSE_WIDGET:
     case MOUSE_OUTSIDE:
       break;