--- a/HierarchicalListView.st	Thu Jul 25 13:00:23 2019 +0200
+++ b/HierarchicalListView.st	Thu Jul 25 14:02:11 2019 +0200
@@ -1,5 +1,3 @@
-"{ Encoding: utf8 }"
-
 "
  COPYRIGHT (c) 1999 by eXept Software AG
 	      All Rights Reserved
@@ -770,7 +768,7 @@
 
     super listChangedInsert:firstAddedIndex nItems:nLines.
 
-    item := self last.
+    (item := self last) isNil ifTrue:[^ self].
     levelOfLastItem := item level.
 
     (     shown
@@ -780,54 +778,65 @@
      and:[(item := self at:firstAddedIndex ifAbsent:nil) notNil
      and:[(level := item level) > 1]]]]]
     ) ifFalse:[
-	^ self.
+        ^ self.
     ].
     xLft := self xVisibleOfVerticalLineAt:level.
 
     (xLft > margin and:[xLft < (width - margin)]) ifFalse:[
-	^ self
+        ^ self
     ].
     start := firstAddedIndex - 1.
 
     start to:1 by:-1 do:[:i| |el|
-	el := self at:i.
+        el := self at:i.
 
-	el level <= level ifTrue:[
-	    i == start ifTrue:[^ self].
+        el level <= level ifTrue:[
+            i == start ifTrue:[^ self].
 
-	    yTop := (self yVisibleOfLine:i + 1) max:margin.
-	    maxY := height - margin.
+            yTop := (self yVisibleOfLine:i + 1) max:margin.
+            maxY := height - margin.
 
-	    yTop < maxY ifTrue:[
-		yBot := (self yVisibleOfLine:firstAddedIndex) - 1 min:maxY.
-		self invalidate:(Rectangle left:xLft top:yTop width:2 height:(yBot - yTop))
-	    ].
-	    ^ self
-	]
+            yTop < maxY ifTrue:[
+                yBot := (self yVisibleOfLine:firstAddedIndex) - 1 min:maxY.
+                self invalidate:(Rectangle left:xLft top:yTop width:2 height:(yBot - yTop))
+            ].
+            ^ self
+        ]
     ].
+
+    "Modified: / 25-07-2019 / 13:58:59 / Claus Gittinger"
 !
 
 listChangedRemove:aStart toIndex:aStop
     "test whether last items are deleted;
      than we have to redraw lines because of different levels
     "
-    |listSize index y0 searchLevel|
+    |listSize index y0 searchLevel item|
 
     listSize    := self size.
     searchLevel := levelOfLastItem.
 
-    listSize == 0 ifTrue:[ levelOfLastItem := 1 ]
-		 ifFalse:[ levelOfLastItem := self last level ].
+    listSize == 0 ifTrue:[ 
+        levelOfLastItem := 1 
+    ] ifFalse:[ 
+        (item := self last) isNil ifTrue:[
+            levelOfLastItem := 1 
+        ] ifFalse:[    
+            levelOfLastItem := item level 
+        ].
+    ].
 
     (shown and:[showLines and:[listSize ~~ 0 and:[aStart > listSize]]]) ifTrue:[
-	index := self findLast:[:el| el level <= searchLevel ].
+        index := self findLast:[:el| el level <= searchLevel ].
 
-	(index ~~ 0 and:[index < listSize]) ifTrue:[
-	    y0 := (self yVisibleOfLine:index) max:margin.
-	    self invalidateX:0 y:y0 width:width height:(height - margin - y0).
-	]
+        (index ~~ 0 and:[index < listSize]) ifTrue:[
+            y0 := (self yVisibleOfLine:index) max:margin.
+            self invalidateX:0 y:y0 width:width height:(height - margin - y0).
+        ]
     ].
     ^ super listChangedRemove:aStart toIndex:aStop
+
+    "Modified: / 25-07-2019 / 14:01:35 / Claus Gittinger"
 !
 
 updateFromList:what with:aPara