Bug 239015 [Databinding] ObservableListTreeContentProvider adds the value passed to TreeViewer#setInput() to the known-elements
The input element is never shown in the viewer so it should no get part of the knownElements further more it restricts the usability of the content-provider because the input-element itself already has to provide the required Observable-Attribute(s).
tests/org.eclipse.jface.tests.databinding/src/org/eclipse/jface/tests/databinding/BindingTestSuite.java
addTestSuite(AbstractObservableMapTest.class);
		addTestSuite(ObservableMapTest.class);
		addTestSuite(WritableMapTest.class);
		addTestSuite(CompositeMapTest.class);
		
		addTest(AbstractObservableSetTest.suite());
		addTest(ObservableSetTest.suite());
		addTest(UnionSetTest.suite());
		addTest(WritableSetTest.suite());
		
		
		addTestSuite(AbstractObservableValueTest.class);
		addTestSuite(AbstractVetoableValueTest.class);
		addTestSuite(ComputedValueTest.class);
		addTest(WritableValueTest.suite());
		
		
		addTestSuite(MultiValidatorTest.class);
		addTestSuite(ValidationStatusTest.class);
		
		
		addTestSuite(BindingMessagesTest.class);
		addTestSuite(BindingStatusTest.class);
		addTestSuite(RandomAccessListIteratorTest.class);
		addTestSuite(QueueTest.class);
		
		addTestSuite(DateConversionSupportTest.class);
		addTestSuite(IdentityConverterTest.class);
		addTestSuite(IntegerToStringConverterTest.class);
		addTestSuite(NumberToBigDecimalTest.class);