Hello,
my collection implements IList interface but doesn't have IsReadOnly or IsFixedSize set.
My items in my collection don't have anything related to ICollectionItemPropertyDescriptor and I didn't override the CanRemove property.
I can't find either this code or any CanRemove property in your "Collection New Items" QuickStart. Neither any ListItemPropertyDescriptor. Not even in the entire solution.
Is there a new version of your samples ?