Bug 197113 Project Explorer drag and drop selection not working properly
Create a new java project. Open Project Explorer. Create 2 new classes - Test1 and Test2. Close the java code editors. Select Test1.java in the project explorer. Select Test2.java by doing a mouse down only (so Test1.java still appears highlighted) then drag Test2.java into the code editor area ()- Test1.java is displayed. This only occurs in the Project Explorer, the package explorer works fine.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonViewer.java
* @see ContentViewer#handleLabelProviderChanged(LabelProviderChangedEvent)
	 */
	protected void handleLabelProviderChanged(LabelProviderChangedEvent event) {
		Object[] changed = event.getElements();
		if (changed != null) {
			List others = Arrays.asList(changed);
			for (Iterator iter = others.iterator(); iter.hasNext();) {
				if(iter.next() == null)
					iter.remove(); 
			} 
			if (others.isEmpty()) {
				return;
			}
			event = new LabelProviderChangedEvent((IBaseLabelProvider) event
					.getSource(), others.toArray());
		}
		super.handleLabelProviderChanged(event);
	}
	protected void handleDispose(DisposeEvent event) {
		dispose();
		super.handleDispose(event);
	}
 
	/**
	 * <p>
	 * Disposes of the NavigatorContentService, which will dispose the Content
	 * and Label providers.
	 * </p>
	 */
	public void dispose() {