--- a/Tools__CodeHighlightingService.st	Wed May 18 14:56:05 2016 +0200
+++ b/Tools__CodeHighlightingService.st	Wed May 18 15:13:46 2016 +0200
@@ -1,5 +1,3 @@
-"{ Encoding: utf8 }"
-
 "
  COPYRIGHT (c) 2010 by Jan Vrany, SWING Research Group. CTU in Prague
               All Rights Reserved
@@ -178,6 +176,22 @@
 
 !CodeHighlightingService methodsFor:'private'!
 
+clearScrollbarBackground
+    "/ immediate change the scroller back to showing nothing;
+    "/ will get new info, when the highlighter is finished.
+
+    |scroller|
+
+    codeView notNil ifTrue:[
+        scroller := textView superView verticalScrollBar thumb.
+        scroller shown ifTrue:[
+            scroller
+                initStyle ;
+                invalidateRepairNow:true.
+        ]
+    ].    
+!
+
 process
     "(Re)starts the processing job. Should be called whenever a source 
      must be (re)processed."
@@ -281,6 +295,7 @@
                                             textView contents: newCode.
                                             codeView syntaxElements: elements.
                                             gutterView invalidate.
+                                            codeView updateScrollersViewBackground.
                                         ]
                                     ]
                                 ]
@@ -388,7 +403,8 @@
     ].
     codeView syntaxElements: elements.
     gutterView invalidate.
-
+    codeView updateScrollersViewBackground.
+    
 "/    Transcript showCR:'--> rehighlighted ', self identityHash printString.
 
     "Modified: / 09-10-2006 / 11:50:17 / cg"