[news.eclipse.platform] custom toolbar at bottom left using new API

[Will Horn <will.horn@xxxxxxxxx>]

I'm trying to add a toolbar using the org.eclipse.ui.menus extension 
point without resorting to deprecated elements.

However, I have not been able to figure out how to get it at the extreme 
 left of the bottom trim.  Using the deprecated group, this works:

      <group
            id="org.myGroup">
         <location>
            <bar type="trim"/>
            <order position="before" relativeTo="status"/>
         </location>
      </group>

However, when I try to use menuContribution and the locationURI 
toolbar:org.eclipse.ui.trim.status, my toolbar always ends up on the far 
right.  From what I can see debugging, there is 
"org.eclipse.jface.action.StatusLineManager" and 
"org.eclipse.ui.internal.progress.ProgressRegion" before my toolbar. 
But I've tried various ?before= and ?after= concoctions and nothing 
seems to make any difference.  Is what I'm trying to do impossible 
declaratively using the new API?