diff --git a/common/content/events.js b/common/content/events.js
index 2b25b6a3..3e643cdc 100644
--- a/common/content/events.js
+++ b/common/content/events.js
@@ -905,7 +905,7 @@ function Events() //{{{
 
             try
             {
-                liberator.threadYield(false, true);
+                liberator.threadYield(1, true);
 
                 noremap = !!noremap;
 
diff --git a/common/content/liberator.js b/common/content/liberator.js
index 98b3871f..68819ed6 100644
--- a/common/content/liberator.js
+++ b/common/content/liberator.js
@@ -1391,7 +1391,7 @@ const liberator = (function () //{{{
                 if (liberator.interrupted)
                     throw new Error("Interrupted");
             }
-            while (flush && mainThread.hasPendingEvents());
+            while (flush === true && mainThread.hasPendingEvents());
         },
 
         variableReference: function (string)