bundles/org.eclipse.rap.ui.workbench/plugin.xml

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>

     <extension
         point="org.eclipse.core.runtime.preferences">
      <initializer
            class="org.eclipse.ui.internal.WorkbenchPreferenceInitializer"/>
   </extension>

</plugin>