Adding a Node with Relationship = etvwPrevious fails

The Add method appears to work, but in fact the node is not added to the TreeView. The error is in the fAdd method of the control, which does not have a handler for the case when eRelation = etvwPrevious. It should find the previous item in the current tree: if one is found then insert the item as the next item to that, otherwise insert it as the first item in the tree.

Fixed.