Bug 135971 [CommonNavigator] Project Explorer: cannot drop to Hierarchy view
You can drag and drop an element onto the Hierarchy view from the Outline or Package Explorer. You cannot from the Project Explorer, you get a drop disabled cursor.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonViewer.java
addDragSupport(operations, dragAdapter.getSupportedDragTransfers(),
				dragAdapter);
		CommonDropAdapter dropAdapter = new CommonDropAdapter(contentService,
				this);
		addDropSupport(operations, dropAdapter.getSupportedDropTransfers(),
				dropAdapter);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#createTreeItem(org.eclipse.swt.widgets.Widget,
	 *      java.lang.Object, int)
	 */
	protected void createTreeItem(Widget parent, final Object element, int index) {
		try {
			super.createTreeItem(parent, element, index);
		} catch (Exception ex) {
			ex.printStackTrace();
		} catch (Error e) {
			e.printStackTrace();
		}
	}
	/*
	 * @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();) {