Bug 1531367 - use root event for history middle clicks to get the correct URI, r=mak

Differential Revision: https://phabricator.services.mozilla.com/D23039

--HG--
extra : moz-landing-system : lando

browser/base/content/browser-places.js

@@ -683,6 +683,7 @@ HistoryMenu.prototype = {
   },
 
   _onCommand: function HM__onCommand(aEvent) {
+    aEvent = getRootEvent(aEvent);
     let placesNode = aEvent.target._placesNode;
     if (placesNode) {
       if (!PrivateBrowsingUtils.isWindowPrivate(window))