diff --git a/layout/generic/nsFrameList.cpp b/layout/generic/nsFrameList.cpp
index be479709749..b80ba0171e8 100644
--- a/layout/generic/nsFrameList.cpp
+++ b/layout/generic/nsFrameList.cpp
@@ -155,6 +155,12 @@ nsFrameList::RemoveFrameIfPresent(nsIFrame* aFrame)
 nsFrameList
 nsFrameList::RemoveFramesAfter(nsIFrame* aAfterFrame)
 {
+  if (!aAfterFrame) {
+    nsFrameList result;
+    result.InsertFrames(nsnull, nsnull, *this);
+    return result;
+  }
+
   NS_PRECONDITION(NotEmpty(), "illegal operation on empty list");
 #ifdef DEBUG_FRAME_LIST
   NS_PRECONDITION(ContainsFrame(aAfterFrame), "wrong list");
diff --git a/layout/generic/nsFrameList.h b/layout/generic/nsFrameList.h
index e8288d2e8bb..7cb750dd97c 100644
--- a/layout/generic/nsFrameList.h
+++ b/layout/generic/nsFrameList.h
@@ -152,8 +152,9 @@ public:
   PRBool RemoveFrameIfPresent(nsIFrame* aFrame);
 
   /**
-   * Take the frames after aAfterFrame out of the frame list.
-   * @param aAfterFrame a frame in this list
+   * Take the frames after aAfterFrame out of the frame list.  If
+   * aAfterFrame is null, removes the entire list.
+   * @param aAfterFrame a frame in this list, or null
    * @return the removed frames, if any
    */
   nsFrameList RemoveFramesAfter(nsIFrame* aAfterFrame);