--- a/HorizontalSteppingSlider.st	Thu Nov 21 19:59:58 1996 +0100
+++ b/HorizontalSteppingSlider.st	Thu Dec 12 14:35:26 1996 +0100
@@ -55,15 +55,22 @@
 !HorizontalSteppingSlider methodsFor:'accessing'!
 
 model:aModel
+    "set the model; this will get the thumbs origin
+     via #value: messages"
+
     thumb model:aModel
 !
 
 start:start stop:stop step:step
+    "set the range and stepIncrement"
+
     thumb start:start stop:stop.
     stepIncrement := step
 !
 
 step
+    "retrieve the stepIncrement"
+
     ^ stepIncrement
 !
 
@@ -114,29 +121,41 @@
 !HorizontalSteppingSlider methodsFor:'misc'!
 
 doesNotUnderstand:aMessage
+    "delegate any unknown messages to my thumb"
+
     ^ aMessage sendTo:thumb 
 ! !
 
 !HorizontalSteppingSlider methodsFor:'private'!
 
-scrollStepDown
-    |nO|
+scrollStep:delta
+    "step by some delta"
+
+    |oldOrg newOrg|
 
-    nO := (thumb thumbOrigin - stepIncrement) max:thumb start.
-    thumb thumbOrigin:nO.
-    thumb tellOthers.
+    oldOrg := thumb thumbOrigin.
+    newOrg := ((oldOrg + delta) max:thumb start) min:thumb stop.
+    oldOrg ~= newOrg ifTrue:[
+        thumb thumbOrigin:newOrg.
+        thumb tellOthers.
+    ]
+!
+
+scrollStepDown
+    "stepDown"
+
+    self scrollStep:stepIncrement negated
 !
 
 scrollStepUp
-    |nO|
+    "step up"
 
-    nO := (thumb thumbOrigin + stepIncrement) min:thumb stop.         
-    thumb thumbOrigin:nO.
-    thumb tellOthers.
+    self scrollStep:stepIncrement
+
 ! !
 
 !HorizontalSteppingSlider class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libwidg2/HorizontalSteppingSlider.st,v 1.8 1996-05-18 15:43:18 cg Exp $'
+    ^ '$Header: /cvs/stx/stx/libwidg2/HorizontalSteppingSlider.st,v 1.9 1996-12-12 13:35:26 cg Exp $'
 ! !