Bug 71640 [IDE] use of deprecated IExtension.getDeclaringPluginDescriptor()
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/IDEWorkbenchPlugin.java
*
     * @param element the config element defining the extension
     * @param classAttribute the name of the attribute carrying the class
     * @return Object the extension object
     * @throws CoreException
     */
    public static Object createExtension(final IConfigurationElement element,
            final String classAttribute) throws CoreException {
        
        
        IPluginDescriptor plugin = element.getDeclaringExtension()
                .getDeclaringPluginDescriptor();
        if (plugin.isPluginActivated()) {
            return element.createExecutableExtension(classAttribute);
        } else {
            final Object[] ret = new Object[1];
            final CoreException[] exc = new CoreException[1];
            BusyIndicator.showWhile(null, new Runnable() {
                public void run() {
                    try {
                        ret[0] = element
                                .createExecutableExtension(classAttribute);
                    } catch (CoreException e) {
                        exc[0] = e;
                    }
                }
            });
            if (exc[0] != null)
                throw exc[0];
            else