diff --git a/modules/juce_events/messages/juce_MessageManager.cpp b/modules/juce_events/messages/juce_MessageManager.cpp
index 96fb6b4f93..5ee02edd26 100644
--- a/modules/juce_events/messages/juce_MessageManager.cpp
+++ b/modules/juce_events/messages/juce_MessageManager.cpp
@@ -94,8 +94,6 @@ void MessageManager::MessageBase::post()
 #if JUCE_MODAL_LOOPS_PERMITTED && ! (JUCE_MAC || JUCE_IOS)
 void MessageManager::runDispatchLoop()
 {
-    jassert (isThisTheMessageThread()); // must only be called by the message thread
-
     runDispatchLoopUntil (-1);
 }
 
@@ -111,20 +109,17 @@ bool MessageManager::runDispatchLoopUntil (int millisecondsToRunFor)
 
     const int64 endTime = Time::currentTimeMillis() + millisecondsToRunFor;
 
-    while ((millisecondsToRunFor < 0 || endTime > Time::currentTimeMillis())
-            && ! quitMessageReceived)
+    while (! quitMessageReceived)
     {
         JUCE_TRY
         {
             if (! dispatchNextMessageOnSystemQueue (millisecondsToRunFor >= 0))
-            {
-                const int msToWait = (int) (endTime - Time::currentTimeMillis());
-
-                if (msToWait > 0)
-                    Thread::sleep (jmin (5, msToWait));
-            }
+                Thread::sleep (1);
         }
         JUCE_CATCH_EXCEPTION
+
+        if (millisecondsToRunFor >= 0 && Time::currentTimeMillis() >= currentTime)
+            break;
     }
 
     return ! quitMessageReceived;