Problem with missaligned Tab Leader Dots

Hi,
I am using the Rich Text Control and RichEditDocumentServer to generate a TOC for my Report.
As shown in the screenshot I am trying to draw some dots between the TOC entry and the page number given the following code:

C#
private static void SetDimensionPagesTabs(RichEditDocumentServer reds, DocumentRange dimensionsRange) {  
            ParagraphProperties paragraphProps = reds.Document.BeginUpdateParagraphs(dimensionsRange);  
            paragraphProps.LineSpacingMultiplier = 1;  
            TabInfoCollection tabInfos = paragraphProps.BeginUpdateTabs(false);  
            tabInfos.Add(new TabInfo() { Position = 60, Alignment = TabAlignmentType.Left });  
            tabInfos.Add(new TabInfo() { Position = 130, Alignment = TabAlignmentType.Left });  
            tabInfos.Add(new TabInfo() { Position = 1800, Alignment = TabAlignmentType.Right, Leader = TabLeaderType.Dots });  
            tabInfos.Add(new TabInfo() { Position = 1850, Alignment = TabAlignmentType.Right });  
            paragraphProps.EndUpdateTabs(tabInfos);  
            reds.Document.EndUpdateParagraphs(paragraphProps);  
        }  

The problemn is that the leader dots do not go all the way to the next tabstop. Am I missing some settings?
What I expected: The dots fill the gap between the text and the "1800" stop.

Sincerely,
Bernd Boruttau