Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/dnd/CommonDropDescriptorManager.java
NavigatorContentRegistryReader implements
			INavigatorContentExtPtConstants {
		private CommonDropAdapterRegistry() {
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.ui.internal.navigator.extensions.RegistryReader#readElement(org.eclipse.core.runtime.IConfigurationElement)
		 */
		protected boolean readElement(IConfigurationElement element) {
			if (TAG_NAVIGATOR_CONTENT.equals(element.getName())) {
				String id = element.getAttribute(ATT_ID);
				if (id != null) {
					INavigatorContentDescriptor contentDescriptor = CONTENT_DESCRIPTOR_MANAGER
							.getContentDescriptor(id);
					if (contentDescriptor != null) {
						IConfigurationElement[] commonDropAdapter = element
								.getChildren(TAG_COMMON_DROP_ADAPTER);
						if (commonDropAdapter.length == 1) {
							addCommonDropAdapter(contentDescriptor,
									new CommonDropAdapterDescriptor(element));
						}
					}
				}
			}
			return super.readElement(element);
		}
	}
}