Took care of i18n

core/src/main/resources/lib/layout/progressiveRendering.jelly

@@ -35,7 +35,7 @@ THE SOFTWARE.
     </st:documentation>
     <st:adjunct includes="lib.layout.progressiveRendering.progressiveRendering"/>
     <!-- XXX generate an ID so we can use this more than once per page -->
-    <t:progressBar id="status" pos="0" tooltip="${tooltip ?: 'Computation in progress.'}"/><!-- XXX I18N -->
+    <t:progressBar id="status" pos="0" tooltip="${tooltip ?: '%progressMessage'}"/>
     <j:invoke method="start" on="${handler}"/>
     <script>progressivelyRender(<st:bind value="${handler}"/>, <st:out value="${callback}"/>);</script>
 </j:jelly>

core/src/main/resources/lib/layout/progressiveRendering.properties

+progressMessage=Computation in progress.
\ No newline at end of file