65411 - add throbber-box id, r=hwaara, sr=sspitzer

mailnews/base/resources/content/mailWindowOverlay.xul

@@ -1113,7 +1113,7 @@ Rights Reserved.
   	  </menubutton>
 			<button class="button-toolbar-2 top" id="button-stop" value="&stopButton.label;"  tooltip="aTooltip" tooltiptext="&stopButton.tooltip;" oncommand="MsgStop();"/>
 			<spring flex="1"/>
-            <box autostretch="never">
+            <box id="throbber-box" autostretch="never">
   	            <button id="navigator-throbber" oncommand='goClickThrobber("messenger.throbber.url")'/>
             </box>
 		</box>

mailnews/compose/resources/content/messengercompose.xul

@@ -437,7 +437,7 @@
                tooltip="aTooltip" tooltiptext="&saveButton.tooltip;" 
                observes="cmd_saveDefault"/>
        <spring flex="1"/>
-       <box autostretch="never">
+       <box id="throbber-box" autostretch="never">
          <button id="navigator-throbber" 
                oncommand="goClickThrobber('compose.throbber.url')">
            <observes element="broadcaster_throbber" attribute="busy"/>