Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/dnd/CommonDropAdapterDescriptor.java
*         extension.
	 */
	public boolean isDropElementSupported(Object anElement) {
		if (dropExpr != null)
			try {
				return dropExpr
						.evaluate(new EvaluationContext(null, anElement)) == EvaluationResult.TRUE;
			} catch (CoreException e) {
				NavigatorPlugin.logError(0, e.getMessage(), e);
			}
		return false;
	}
	/**
	 * 
	 * @return An instance of {@link CommonDropAdapterAssistant} from the
	 *         descriptor or {@link SkeletonCommonDropAssistant}.
	 */
	public CommonDropAdapterAssistant createDropAssistant() {
		try {
			return (CommonDropAdapterAssistant) element
					.createExecutableExtension(ATT_CLASS);
		} catch (CoreException e) {
			NavigatorPlugin.logError(0, e.getMessage(), e);
		} catch (RuntimeException re) {
			NavigatorPlugin.logError(0, re.getMessage(), re);
		}
		return SkeletonCommonDropAssistant.INSTANCE;
	}
}