--- a/browser/base/content/browser-social.js
+++ b/browser/base/content/browser-social.js
@@ -1025,17 +1025,21 @@ var SocialToolbar = {
         }, true);
       }
     });
 
     let navBar = document.getElementById("nav-bar");
     let anchor = navBar.getAttribute("mode") == "text" ?
                    document.getAnonymousElementByAttribute(aToolbarButton, "class", "toolbarbutton-text") :
                    document.getAnonymousElementByAttribute(aToolbarButton, "class", "toolbarbutton-icon");
-    panel.openPopup(anchor, "bottomcenter topright", 0, 0, false, false);
+    // Bug 849216 - open the popup in a setTimeout so we avoid the auto-rollup
+    // handling from preventing it being opened in some cases.
+    setTimeout(function() {
+      panel.openPopup(anchor, "bottomcenter topright", 0, 0, false, false);
+    }, 0);
   },
 
   setPanelErrorMessage: function SocialToolbar_setPanelErrorMessage(aNotificationFrame) {
     if (!aNotificationFrame)
       return;
 
     let src = aNotificationFrame.getAttribute("src");
     aNotificationFrame.removeAttribute("src");