As mentioned in Discussion
there seems to be an issue with AvalonDock 2.0 when used through COM Object Generation/Call.
After the Thread from ShadesJeff I've decided to dig a bit deeper, but as stated I'm not good in this type of debugging.
I can confirm, that the Error is may be around the LayoutPanel and the Processing of Childs.
I'm not sure but guess it shouldn't be normal, that the child will be reprocessed multiple time for sizing/location (at least it looks like: First at Init LayoutPane, 2nd after Orientation-Check/Reset of the LayoutPane).
Simplified Flow explained
: Init - Childs - Orientation - Crash
: Init - Childs - Orientation - Childs again - Show
I'll hope this explanation and the demo files help to find the real issue.
Sorry for not beeing a better help in it.
Forgot to Mention:
AvalonDock 1.3 works perfectly through COM (But I know this will not help for fixing the issue)