Comment 10 for bug 721786

This is really annoying (but still better than the overlay monstrosity :-)

It can be simply fixed by editing:
/usr/share/themes/Ambiance
gtk-2.0/gtkrc and gtk-3.0/gtk-widgets.css

My current "orange" quick-fix is (I didn't bother to invert the white gtk3 border):

diff --git a/gtk-2.0/gtkrc b/gtk-2.0/gtkrc
index 6da693e..29fa473 100644
--- a/gtk-2.0/gtkrc
+++ b/gtk-2.0/gtkrc
@@ -105,7 +105,7 @@ style "default" {
                lightborderstyle = 1
                listviewstyle = 2
                progressbarstyle = 0
- colorize_scrollbar = FALSE
+ colorize_scrollbar = TRUE
                menubaritemstyle = 1
                menubarstyle = 1
                menustyle = 0
@@ -232,7 +232,7 @@ style "scrollbar" = "button" {
        engine "murrine"
        {
                border_shades = {0.95, 0.90}
- roundness = 20
+ roundness = 3
                contrast = 1.0
                trough_shades = {0.92, 0.98}
                lightborder_shade = 1.3
----
diff --git a/gtk-3.0/gtk-widgets.css b/gtk-3.0/gtk-widgets.css
index 51d817c..0ce659d 100644
--- a/gtk-3.0/gtk-widgets.css
+++ b/gtk-3.0/gtk-widgets.css
@@ -1544,12 +1544,13 @@ GtkScale.mark {
 /*************
  * scrollbar *
  *************/
+@define-color blk #464540;
 .scrollbar {
     -GtkScrollbar-has-backward-stepper: 0;
     -GtkScrollbar-has-forward-stepper: 0;
     -GtkRange-slider-width: 13;

- border-radius: 20px;
+ border-radius: 3px;

     -unico-border-gradient: -gtk-gradient (linear, left top, left bottom,
                                            from (shade (@bg_color, 0.74)),
@@ -1584,8 +1585,10 @@ GtkScale.mark {
 .scrollbar.slider.vertical:hover,
 .scrollbar.button.vertical {
     background-image: -gtk-gradient (linear, left top, right top,
- from (shade (@bg_color, 1.08)),
- to (shade (@bg_color, 0.92)));
+ from (shade (@blk, 1.08)),
+ to (shade (@blk, 0.92)));
+
+/* background-color:#e96d3b; */
     border-style: solid;
     border-width: 1px;

@@ -1603,8 +1606,8 @@ GtkScale.mark {
 .scrollbar.slider.horizontal:hover,
 .scrollbar.button.horizontal {
     background-image: -gtk-gradient (linear, left top, left bottom,
- from (shade (@bg_color, 1.08)),
- to (shade (@bg_color, 0.92)));
+ from (shade (@blk, 1.08)),
+ to (shade (@blk, 0.92)));

     -unico-border-gradient: -gtk-gradient (linear, left top, left bottom,
                                            from (shade (@bg_color, 0.74)),