Commented Issue: AvalonDock.TestApp null exception [15239]

Run AvalonDock.TestApp, click add 2 documents button. go to left to pin created window. go to document area, click document2 , an exception is thrown at:

LayoutAnchorGroupControl: line 75: var manager = _model.Root.Manager;
Comments: ** Comment from web user: huangzl99 **

The bug is from build 2.0.0832.