diff --git a/common/content/modes.js b/common/content/modes.js
index 889abcd2..127fa95a 100644
--- a/common/content/modes.js
+++ b/common/content/modes.js
@@ -299,7 +299,7 @@ var Modes = Module("modes", {
             return;
         }
 
-        params = params || this.getMode(mainMode || this.main).params;
+        params = params || Object.create(this.getMode(mainMode || this.main).params);
 
         if (!stack && mainMode != null && this._modeStack.length > 1)
             this.reset();
diff --git a/common/modules/bookmarkcache.jsm b/common/modules/bookmarkcache.jsm
index 7896290f..8183615c 100644
--- a/common/modules/bookmarkcache.jsm
+++ b/common/modules/bookmarkcache.jsm
@@ -184,7 +184,11 @@ var BookmarkCache = Module("BookmarkCache", XPCOM(Ci.nsINavBookmarkObserver), {
         let query = services.history.getNewQuery();
         let options = services.history.getNewQueryOptions();
         options.queryType = options.QUERY_TYPE_BOOKMARKS;
-        options.excludeItemIfParentHasAnnotation = "livemark/feedURI";
+        try {
+            // https://bugzil.la/702639
+            options.excludeItemIfParentHasAnnotation = "livemark/feedURI";
+        }
+        catch (e) {}
 
         let { root } = services.history.executeQuery(query, options);
         root.containerOpen = true;