diff --git a/content/events/src/nsEventStateManager.cpp b/content/events/src/nsEventStateManager.cpp
index adcd9902ec6..d7595998a56 100644
--- a/content/events/src/nsEventStateManager.cpp
+++ b/content/events/src/nsEventStateManager.cpp
@@ -2684,12 +2684,11 @@ nsEventStateManager::DoScrollText(nsPresContext* aPresContext,
     }
     
     if (aScrollQuantity == eScrollByPage)
-      scrollView->ScrollByPages(scrollX, scrollY, NS_VMREFRESH_DEFERRED);
+      scrollView->ScrollByPages(scrollX, scrollY, NS_VMREFRESH_SMOOTHSCROLL);
     else if (aScrollQuantity == eScrollByPixel)
       scrollView->ScrollByPixels(scrollX, scrollY, NS_VMREFRESH_DEFERRED);
     else
-      scrollView->ScrollByLines(scrollX, scrollY,
-                                NS_VMREFRESH_SMOOTHSCROLL | NS_VMREFRESH_DEFERRED);
+      scrollView->ScrollByLines(scrollX, scrollY, NS_VMREFRESH_SMOOTHSCROLL);
   }
   if (passToParent) {
     nsresult rv;
@@ -3158,7 +3157,8 @@ nsEventStateManager::PostHandleEvent(nsPresContext* aPresContext,
               nsIScrollableView* sv = nsLayoutUtils::GetNearestScrollingView(aView, nsLayoutUtils::eVertical);
               if (sv) {
                 nsKeyEvent * keyEvent = (nsKeyEvent *)aEvent;
-                sv->ScrollByPages(0, (keyEvent->keyCode != NS_VK_PAGE_UP) ? 1 : -1);
+                sv->ScrollByPages(0, (keyEvent->keyCode != NS_VK_PAGE_UP) ? 1 : -1,
+                                  NS_VMREFRESH_SMOOTHSCROLL);
               }
             }
             break;
@@ -3178,7 +3178,8 @@ nsEventStateManager::PostHandleEvent(nsPresContext* aPresContext,
               nsIScrollableView* sv = nsLayoutUtils::GetNearestScrollingView(aView, nsLayoutUtils::eVertical);
               if (sv) {
                 nsKeyEvent * keyEvent = (nsKeyEvent *)aEvent;
-                sv->ScrollByLines(0, (keyEvent->keyCode == NS_VK_DOWN) ? 1 : -1);
+                sv->ScrollByLines(0, (keyEvent->keyCode == NS_VK_DOWN) ? 1 : -1,
+                                  NS_VMREFRESH_SMOOTHSCROLL);
 
                 // force the update to happen now, otherwise multiple scrolls can
                 // occur before the update is processed. (bug #7354)
@@ -3197,7 +3198,8 @@ nsEventStateManager::PostHandleEvent(nsPresContext* aPresContext,
               nsIScrollableView* sv = nsLayoutUtils::GetNearestScrollingView(aView, nsLayoutUtils::eHorizontal);
               if (sv) {
                 nsKeyEvent * keyEvent = (nsKeyEvent *)aEvent;
-                sv->ScrollByLines((keyEvent->keyCode == NS_VK_RIGHT) ? 1 : -1, 0);
+                sv->ScrollByLines((keyEvent->keyCode == NS_VK_RIGHT) ? 1 : -1, 0,
+                                  NS_VMREFRESH_SMOOTHSCROLL);
 
                 // force the update to happen now, otherwise multiple scrolls can
                 // occur before the update is processed. (bug #7354)
@@ -3218,7 +3220,7 @@ nsEventStateManager::PostHandleEvent(nsPresContext* aPresContext,
               if (!mCurrentFocus) {
                 nsIScrollableView* sv = nsLayoutUtils::GetNearestScrollingView(aView, nsLayoutUtils::eVertical);
                 if (sv) {
-                  sv->ScrollByPages(0, 1);
+                  sv->ScrollByPages(0, 1, NS_VMREFRESH_SMOOTHSCROLL);
                 }
               }
             }
diff --git a/docshell/test/navigation/test_bug430723.html b/docshell/test/navigation/test_bug430723.html
index 9d8c2929477..deb38cb5489 100644
--- a/docshell/test/navigation/test_bug430723.html
+++ b/docshell/test/navigation/test_bug430723.html
@@ -65,11 +65,13 @@ var step1 =function() {
      "Page1: Ensure we scrollpane is at the top before we start scrolling.");
   sendKey('DOWN', testWindow);
   sendKey('UP', testWindow);
-  is(testWindow.document.body.scrollTop, 0,
-     "Page1: Ensure we can scroll down and up, back to the top.");  
-  
-  // Nav to blue box page. This should fire step2.
-  testWindow.location = gTallBlueBoxURI;
+  setTimeout(function() {
+    is(testWindow.document.body.scrollTop, 0,
+       "Page1: Ensure we can scroll down and up, back to the top.");  
+    
+    // Nav to blue box page. This should fire step2.
+    testWindow.location = gTallBlueBoxURI;
+  }, 0);
 }
 
 
@@ -82,11 +84,13 @@ var step2 =function() {
   sendKey('DOWN', testWindow);
   sendKey('DOWN', testWindow);
   sendKey('DOWN', testWindow);
-  isnot(testWindow.document.body.scrollTop, 0,
-        "Page2: Ensure we could scrol.");  
-  
-  // Navigate backwards. This should fire step3.
-  testWindow.history.back();
+  setTimeout(function() {
+    isnot(testWindow.document.body.scrollTop, 0,
+          "Page2: Ensure we could scrol.");  
+    
+    // Navigate backwards. This should fire step3.
+    testWindow.history.back();
+  }, 0);
 }
 
 var step3 =function() {
@@ -97,11 +101,13 @@ var step3 =function() {
   is(testWindow.document.body.scrollTop, 0,
      "Page1Again: Ensure scroll pane at top before we scroll.");  
   sendKey('DOWN', testWindow);
-  isnot(testWindow.document.body.scrollTop, 0,
-        "Page2Again: Ensure we can still scroll.");  
-  
-  testWindow.close();
-  window.SimpleTest.finish();
+  setTimeout(function() {
+    isnot(testWindow.document.body.scrollTop, 0,
+          "Page2Again: Ensure we can still scroll.");  
+    
+    testWindow.close();
+    window.SimpleTest.finish();
+  }, 0);
 }
 
 SimpleTest.waitForExplicitFinish();
diff --git a/editor/libeditor/base/tests/test_selection_move_commands.xul b/editor/libeditor/base/tests/test_selection_move_commands.xul
index 514144c6322..fae1c310c0a 100644
--- a/editor/libeditor/base/tests/test_selection_move_commands.xul
+++ b/editor/libeditor/base/tests/test_selection_move_commands.xul
@@ -11,6 +11,17 @@
 <![CDATA[
 
 function runTest() {
+  var tests = execTests();
+  function execNext() {
+    try {
+      tests.next();
+      setTimeout(execNext, 0);
+    } catch (e) {}
+  }
+  execNext();
+}
+
+function execTests() {
   var e = document.getElementById("edit");
   var doc = e.contentDocument;
   var win = e.contentWindow;
@@ -39,7 +50,6 @@ function runTest() {
   }
 
   function testScrollCommand(cmd, expectTop) {
-    doCommand(cmd);
     is(root.getBoundingClientRect().top, -expectTop, cmd);
   }
 
@@ -100,21 +110,29 @@ function runTest() {
     return n;
   }
 
+  doCommand("cmd_scrollBottom");
   testScrollCommand("cmd_scrollBottom", root.scrollHeight - 100);
+  doCommand("cmd_scrollTop");
   testScrollCommand("cmd_scrollTop", 0);
 
   doCommand("cmd_scrollPageDown");
+  yield;
   var pageHeight = -root.getBoundingClientRect().top;
   ok(pageHeight > 0, "cmd_scrollPageDown works");
   ok(pageHeight <= 100, "cmd_scrollPageDown doesn't scroll too much");
   doCommand("cmd_scrollBottom");
+  doCommand("cmd_scrollPageUp");
+  yield;
   testScrollCommand("cmd_scrollPageUp", root.scrollHeight - 100 - pageHeight);
 
   doCommand("cmd_scrollTop");
   doCommand("cmd_scrollLineDown");
+  yield;
   var lineHeight = -root.getBoundingClientRect().top;
   ok(lineHeight > 0, "Can scroll by lines");
   doCommand("cmd_scrollBottom");
+  doCommand("cmd_scrollLineUp");
+  yield;
   testScrollCommand("cmd_scrollLineUp", root.scrollHeight - 100 - lineHeight);
 
   var runSelectionTests = function(selectWordNextNode, selectWordNextOffset) {
diff --git a/layout/base/nsPresShell.cpp b/layout/base/nsPresShell.cpp
index ed58e9eeac7..fe5759d4f6c 100644
--- a/layout/base/nsPresShell.cpp
+++ b/layout/base/nsPresShell.cpp
@@ -2835,7 +2835,7 @@ PresShell::ScrollPage(PRBool aForward)
 {
   nsIScrollableView* scrollView = GetViewToScroll(nsLayoutUtils::eVertical);
   if (scrollView) {
-    scrollView->ScrollByPages(0, aForward ? 1 : -1);
+    scrollView->ScrollByPages(0, aForward ? 1 : -1, NS_VMREFRESH_SMOOTHSCROLL);
   }
   return NS_OK;
 }
@@ -2848,9 +2848,9 @@ PresShell::ScrollLine(PRBool aForward)
 #ifdef MOZ_WIDGET_COCOA
     // Emulate the Mac IE behavior of scrolling a minimum of 2 lines
     // rather than 1.  This vastly improves scrolling speed.
-    scrollView->ScrollByLines(0, aForward ? 2 : -2);
+    scrollView->ScrollByLines(0, aForward ? 2 : -2, NS_VMREFRESH_SMOOTHSCROLL);
 #else
-    scrollView->ScrollByLines(0, aForward ? 1 : -1);
+    scrollView->ScrollByLines(0, aForward ? 1 : -1, NS_VMREFRESH_SMOOTHSCROLL);
 #endif
       
 //NEW FOR LINES    
@@ -2872,7 +2872,7 @@ PresShell::ScrollHorizontal(PRBool aLeft)
 {
   nsIScrollableView* scrollView = GetViewToScroll(nsLayoutUtils::eHorizontal);
   if (scrollView) {
-    scrollView->ScrollByLines(aLeft ? -1 : 1, 0);
+    scrollView->ScrollByLines(aLeft ? -1 : 1, 0, NS_VMREFRESH_SMOOTHSCROLL);
 //NEW FOR LINES    
     // force the update to happen now, otherwise multiple scrolls can
     // occur before the update is processed. (bug #7354)
diff --git a/layout/generic/nsGfxScrollFrame.cpp b/layout/generic/nsGfxScrollFrame.cpp
index 6748180f3b9..22e3c07bf6c 100644
--- a/layout/generic/nsGfxScrollFrame.cpp
+++ b/layout/generic/nsGfxScrollFrame.cpp
@@ -1910,7 +1910,8 @@ void nsGfxScrollFrameInner::CurPosAttributeChanged(nsIContent* aContent)
       InternalScrollPositionDidChange(curPosX, curPosY);
       mFrameInitiatedScroll = PR_FALSE;
     }
-    ScrollbarChanged(mOuter->PresContext(), x, y, isSmooth ? NS_VMREFRESH_SMOOTHSCROLL : 0);
+    ScrollbarChanged(mOuter->PresContext(), x, y,
+                     isSmooth ? NS_VMREFRESH_SMOOTHSCROLL : NS_VMREFRESH_DEFERRED);
   }
 }
 
diff --git a/view/src/nsScrollPortView.cpp b/view/src/nsScrollPortView.cpp
index 8872f007905..8f6fb574d0c 100644
--- a/view/src/nsScrollPortView.cpp
+++ b/view/src/nsScrollPortView.cpp
@@ -255,7 +255,7 @@ NS_IMETHODIMP nsScrollPortView::ScrollTo(nscoord aDestinationX, nscoord aDestina
   mDestinationY = aDestinationY;
   ClampScrollValues(mDestinationX, mDestinationY, this);
 
-  if (!(aUpdateFlags & NS_VMREFRESH_DEFERRED)) {
+  if (!(aUpdateFlags & (NS_VMREFRESH_DEFERRED | NS_VMREFRESH_SMOOTHSCROLL))) {
     // Asynchronous scrolling is not allowed, so we'll kill any existing
     // async-scrolling process and do an instant scroll
     delete mAsyncScroll;