Outlining regions default collapsing does not seem to work

Hi,

I am creating Visual Studio 2012 extension following MSDN Walkthrough: Outlining article (I am sorry for not providing link, this forum does not allow me) and all works as expected (I.e. I am able to create my own outlining regions) until I want my newly created outlining regions to collapse by default.

What I do is changing following example code from the walkthrough from

yield return new TagSpan<IOutliningRegionTag>
(
  new SnapshotSpan(startLine.Start + region.StartOffset, endLine.End),
  new OutliningRegionTag(false, false, ellipsis, hoverText)
);

to

yield return new TagSpan<IOutliningRegionTag>
(
  new SnapshotSpan(startLine.Start + region.StartOffset, endLine.End),
  new OutliningRegionTag(true, false, ellipsis, hoverText)
); 

So basically I only change the first parameter (bool isDefaultCollapsed) ofOutliningRegionTag constructor from 'false' to 'true' and I expect the region to be collapsed by default after it is created. Unfortunately my regions are still expanded and react only to manual collapse/expand by clicking the +/- symbols.

Is my expectation wrong? Do I understand something wrong? Is there any other way to achieve what I want (i.e. having newly created outline regions collapsed on demand)?

Thank you,

Otakar Nieder