Bug 550262 - CCE in Categorization with composite categories and tabs

* do not cast without check anymore
* respond to the view model's selection property only if the new child
is actually a part of our subtree (with Tabs we have more than one tree)

Change-Id: I970c6eeab133ff4fda6ad95500ee8368b7232f81
Signed-off-by: Johannes Faltermeier <jfaltermeier@eclipsesource.com>
1 file changed