#17 Property for Begin-/EndUpdate()

[Goni]

I'm currently trying to implement DataBinding analog to the DataTableExample for that control, e.g. a property for the parentKeyMember and a property for the keyMember, which specify the tree structure. I'm getting stuck when it comes to any updates to the treemodel. I would like to defer some updates on the TreeModel when for example both properties (key and parentKey) are changed.
A property on the TreeViewAdv control to get a value whether BeginUpdate() was called would be nice. I could use the SuspendSelectionEvent but its only internal.
Could you also please make Begin-/EndUpdate() virtual, so that i can easily override it?