diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 0c11c81f6ac8..b7a43813a587 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -2828,48 +2828,28 @@ nsBlockFrame::SlideLine(nsBlockReflowState& aState,
   }
 
   if (aLine->IsBlock()) {
-    nsRect r;
-    kid->GetRect(r);
     if (aDY) {
-      r.y += aDY;
-      kid->SetRect(aState.mPresContext, r);
+      nsPoint p;
+      kid->GetOrigin(p);
+      p.y += aDY;
+      kid->MoveTo(aState.mPresContext, p.x, p.y);
     }
 
     // Make sure the frame's view and any child views are updated
     ::PlaceFrameView(aState.mPresContext, kid);
-
-    // If the child has any floaters that impact the space-manager,
-    // place them now so that they are present in the space-manager
-    // again (they were removed by the space-manager's frame when
-    // the reflow began).
-    nsBlockFrame* bf;
-    nsresult rv = kid->QueryInterface(kBlockFrameCID, (void**) &bf);
-    if (NS_SUCCEEDED(rv)) {
-      // Translate spacemanager to the child blocks upper-left corner
-      // so that when it places its floaters (which are relative to
-      // it) the right coordinates are used. Note that we have already
-      // been translated by our border+padding so factor that in to
-      // get the right translation.
-      const nsMargin& bp = aState.BorderPadding();
-      nscoord dx = r.x - bp.left;
-      nscoord dy = r.y - bp.top;
-      aState.mSpaceManager->Translate(dx, dy);
-      bf->UpdateSpaceManager(aState.mPresContext, aState.mSpaceManager);
-      aState.mSpaceManager->Translate(-dx, -dy);
-    }
   }
   else {
     // Adjust the Y coordinate of the frames in the line.
     // Note: we need to re-position views even if aDY is 0, because
     // one of our parent frames may have moved and so the view's position
     // relative to its parent may have changed
-    nsRect r;
     PRInt32 n = aLine->GetChildCount();
     while (--n >= 0) {
       if (aDY) {
-        kid->GetRect(r);
-        r.y += aDY;
-        kid->SetRect(aState.mPresContext, r);
+        nsPoint p;
+        kid->GetOrigin(p);
+        p.y += aDY;
+        kid->MoveTo(aState.mPresContext, p.x, p.y);
       }
       // Make sure the frame's view and any child views are updated
       ::PlaceFrameView(aState.mPresContext, kid);
@@ -2878,58 +2858,6 @@ nsBlockFrame::SlideLine(nsBlockReflowState& aState,
   }
 }
 
-nsresult
-nsBlockFrame::UpdateSpaceManager(nsIPresContext* aPresContext,
-                                 nsSpaceManager* aSpaceManager)
-{
-  for (line_iterator line = begin_lines(), line_end = end_lines();
-       line != line_end;
-       ++line) {
-    // Place the floaters in the spacemanager
-    if (line->HasFloaters()) {
-      nsFloaterCache* fc = line->GetFirstFloater();
-      while (fc) {
-        nsIFrame* floater = fc->mPlaceholder->GetOutOfFlowFrame();
-        aSpaceManager->AddRectRegion(floater, fc->mRegion);
-#ifdef NOISY_SPACEMANAGER
-        nscoord tx, ty;
-        aSpaceManager->GetTranslation(tx, ty);
-        nsFrame::ListTag(stdout, this);
-        printf(": UpdateSpaceManager: AddRectRegion: txy=%d,%d {%d,%d,%d,%d}\n",
-               tx, ty,
-               fc->mRegion.x, fc->mRegion.y,
-               fc->mRegion.width, fc->mRegion.height);
-#endif
-        fc = fc->Next();
-      }
-    }
-
-    // Tell kids about the move too
-    if (line->mFirstChild && line->IsBlock()) {
-      // If the child has any floaters that impact the space-manager,
-      // place them now so that they are present in the space-manager
-      // again (they were removed by the space-manager's frame when
-      // the reflow began).
-      nsBlockFrame* bf;
-      nsresult rv = line->mFirstChild->QueryInterface(kBlockFrameCID,
-                                            NS_REINTERPRET_CAST(void**, &bf));
-      if (NS_SUCCEEDED(rv)) {
-        nsPoint origin;
-        bf->GetOrigin(origin);
-
-        // Translate spacemanager to the child blocks upper-left
-        // corner so that when it places its floaters (which are
-        // relative to it) the right coordinates are used.
-        aSpaceManager->Translate(origin.x, origin.y);
-        bf->UpdateSpaceManager(aPresContext, aSpaceManager);
-        aSpaceManager->Translate(-origin.x, -origin.y);
-      }
-    }
-  }
-
-  return NS_OK;
-}
-
 NS_IMETHODIMP 
 nsBlockFrame::AttributeChanged(nsIPresContext* aPresContext,
                                nsIContent*     aChild,
diff --git a/layout/generic/nsBlockFrame.h b/layout/generic/nsBlockFrame.h
index d4d98fddd169..67fa31dd6369 100644
--- a/layout/generic/nsBlockFrame.h
+++ b/layout/generic/nsBlockFrame.h
@@ -188,12 +188,6 @@ public:
     */
   nsIFrame* GetTopBlockChild();
 
-  /** Place the floaters in the spacemanager for all lines in this block.
-    * recursively adds floaters in child blocks of this frame.
-    */
-  nsresult UpdateSpaceManager(nsIPresContext* aPresContext,
-                              nsSpaceManager* aSpaceManager);
-
   // returns true on success and false if aFoundLine is set to end_lines()
   PRBool FindLineFor(nsIFrame* aFrame,
                      PRBool* aIsFloaterResult,
diff --git a/layout/generic/nsBlockReflowState.cpp b/layout/generic/nsBlockReflowState.cpp
index da944f5f882f..174fbb4608c9 100644
--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -474,6 +474,14 @@ nsBlockReflowState::ReconstructMarginAbove(nsLineList::iterator aLine)
   }
 }
 
+/**
+ * Restore information about floaters into the space manager for an
+ * incremental reflow, and simultaneously push the floaters by
+ * |aDeltaY|, which is the amount |aLine| was pushed relative to its
+ * parent.  The recovery of state is one of the things that makes
+ * incremental reflow O(N^2) and this state should really be kept
+ * around, attached to the frame tree.
+ */
 void
 nsBlockReflowState::RecoverFloaters(nsLineList::iterator aLine,
                                     nscoord aDeltaY)
@@ -481,25 +489,26 @@ nsBlockReflowState::RecoverFloaters(nsLineList::iterator aLine,
   if (aLine->HasFloaters()) {
     // Place the floaters into the space-manager again. Also slide
     // them, just like the regular frames on the line.
-    nsRect r;
     nsFloaterCache* fc = aLine->GetFirstFloater();
     while (fc) {
-      fc->mRegion.y += aDeltaY;
-      fc->mCombinedArea.y += aDeltaY;
       nsIFrame* floater = fc->mPlaceholder->GetOutOfFlowFrame();
-      floater->GetRect(r);
-      floater->MoveTo(mPresContext, r.x, r.y + aDeltaY);
+      if (aDeltaY != 0) {
+        fc->mRegion.y += aDeltaY;
+        fc->mCombinedArea.y += aDeltaY;
+        nsPoint p;
+        floater->GetOrigin(p);
+        floater->MoveTo(mPresContext, p.x, p.y + aDeltaY);
+      }
 #ifdef DEBUG
       if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisySpaceManager) {
         nscoord tx, ty;
         mSpaceManager->GetTranslation(tx, ty);
         nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
-        printf("RecoverState: txy=%d,%d (%d,%d) ",
+        printf("RecoverFloaters: txy=%d,%d (%d,%d) ",
                tx, ty, mSpaceManagerX, mSpaceManagerY);
         nsFrame::ListTag(stdout, floater);
-        printf(" r.y=%d aDeltaY=%d (sum=%d) region={%d,%d,%d,%d}\n",
-               r.y, aDeltaY, r.y + aDeltaY,
-               fc->mRegion.x, fc->mRegion.y,
+        printf(" aDeltaY=%d region={%d,%d,%d,%d}\n",
+               aDeltaY, fc->mRegion.x, fc->mRegion.y,
                fc->mRegion.width, fc->mRegion.height);
       }
 #endif
@@ -511,15 +520,17 @@ nsBlockReflowState::RecoverFloaters(nsLineList::iterator aLine,
     nsBlockFrame *kid = nsnull;
     aLine->mFirstChild->QueryInterface(kBlockFrameCID, (void**)&kid);
     if (kid) {
-      nsRect kidRect;
-      kid->GetRect(kidRect);
-      mSpaceManager->Translate(kidRect.x, kidRect.y);
+      nscoord kidx = kid->mRect.x, kidy = kid->mRect.y;
+      mSpaceManager->Translate(kidx, kidy);
       for (nsBlockFrame::line_iterator line = kid->begin_lines(),
                                    line_end = kid->end_lines();
            line != line_end;
            ++line)
-        RecoverFloaters(line, aDeltaY);
-      mSpaceManager->Translate(-kidRect.x, -kidRect.y);
+        // Pass 0, not the real DeltaY, since these floaters aren't
+        // moving relative to their parent block, only relative to
+        // the space manager.
+        RecoverFloaters(line, 0);
+      mSpaceManager->Translate(-kidx, -kidy);
     }
   }
 }
diff --git a/layout/html/base/src/nsBlockFrame.cpp b/layout/html/base/src/nsBlockFrame.cpp
index 0c11c81f6ac8..b7a43813a587 100644
--- a/layout/html/base/src/nsBlockFrame.cpp
+++ b/layout/html/base/src/nsBlockFrame.cpp
@@ -2828,48 +2828,28 @@ nsBlockFrame::SlideLine(nsBlockReflowState& aState,
   }
 
   if (aLine->IsBlock()) {
-    nsRect r;
-    kid->GetRect(r);
     if (aDY) {
-      r.y += aDY;
-      kid->SetRect(aState.mPresContext, r);
+      nsPoint p;
+      kid->GetOrigin(p);
+      p.y += aDY;
+      kid->MoveTo(aState.mPresContext, p.x, p.y);
     }
 
     // Make sure the frame's view and any child views are updated
     ::PlaceFrameView(aState.mPresContext, kid);
-
-    // If the child has any floaters that impact the space-manager,
-    // place them now so that they are present in the space-manager
-    // again (they were removed by the space-manager's frame when
-    // the reflow began).
-    nsBlockFrame* bf;
-    nsresult rv = kid->QueryInterface(kBlockFrameCID, (void**) &bf);
-    if (NS_SUCCEEDED(rv)) {
-      // Translate spacemanager to the child blocks upper-left corner
-      // so that when it places its floaters (which are relative to
-      // it) the right coordinates are used. Note that we have already
-      // been translated by our border+padding so factor that in to
-      // get the right translation.
-      const nsMargin& bp = aState.BorderPadding();
-      nscoord dx = r.x - bp.left;
-      nscoord dy = r.y - bp.top;
-      aState.mSpaceManager->Translate(dx, dy);
-      bf->UpdateSpaceManager(aState.mPresContext, aState.mSpaceManager);
-      aState.mSpaceManager->Translate(-dx, -dy);
-    }
   }
   else {
     // Adjust the Y coordinate of the frames in the line.
     // Note: we need to re-position views even if aDY is 0, because
     // one of our parent frames may have moved and so the view's position
     // relative to its parent may have changed
-    nsRect r;
     PRInt32 n = aLine->GetChildCount();
     while (--n >= 0) {
       if (aDY) {
-        kid->GetRect(r);
-        r.y += aDY;
-        kid->SetRect(aState.mPresContext, r);
+        nsPoint p;
+        kid->GetOrigin(p);
+        p.y += aDY;
+        kid->MoveTo(aState.mPresContext, p.x, p.y);
       }
       // Make sure the frame's view and any child views are updated
       ::PlaceFrameView(aState.mPresContext, kid);
@@ -2878,58 +2858,6 @@ nsBlockFrame::SlideLine(nsBlockReflowState& aState,
   }
 }
 
-nsresult
-nsBlockFrame::UpdateSpaceManager(nsIPresContext* aPresContext,
-                                 nsSpaceManager* aSpaceManager)
-{
-  for (line_iterator line = begin_lines(), line_end = end_lines();
-       line != line_end;
-       ++line) {
-    // Place the floaters in the spacemanager
-    if (line->HasFloaters()) {
-      nsFloaterCache* fc = line->GetFirstFloater();
-      while (fc) {
-        nsIFrame* floater = fc->mPlaceholder->GetOutOfFlowFrame();
-        aSpaceManager->AddRectRegion(floater, fc->mRegion);
-#ifdef NOISY_SPACEMANAGER
-        nscoord tx, ty;
-        aSpaceManager->GetTranslation(tx, ty);
-        nsFrame::ListTag(stdout, this);
-        printf(": UpdateSpaceManager: AddRectRegion: txy=%d,%d {%d,%d,%d,%d}\n",
-               tx, ty,
-               fc->mRegion.x, fc->mRegion.y,
-               fc->mRegion.width, fc->mRegion.height);
-#endif
-        fc = fc->Next();
-      }
-    }
-
-    // Tell kids about the move too
-    if (line->mFirstChild && line->IsBlock()) {
-      // If the child has any floaters that impact the space-manager,
-      // place them now so that they are present in the space-manager
-      // again (they were removed by the space-manager's frame when
-      // the reflow began).
-      nsBlockFrame* bf;
-      nsresult rv = line->mFirstChild->QueryInterface(kBlockFrameCID,
-                                            NS_REINTERPRET_CAST(void**, &bf));
-      if (NS_SUCCEEDED(rv)) {
-        nsPoint origin;
-        bf->GetOrigin(origin);
-
-        // Translate spacemanager to the child blocks upper-left
-        // corner so that when it places its floaters (which are
-        // relative to it) the right coordinates are used.
-        aSpaceManager->Translate(origin.x, origin.y);
-        bf->UpdateSpaceManager(aPresContext, aSpaceManager);
-        aSpaceManager->Translate(-origin.x, -origin.y);
-      }
-    }
-  }
-
-  return NS_OK;
-}
-
 NS_IMETHODIMP 
 nsBlockFrame::AttributeChanged(nsIPresContext* aPresContext,
                                nsIContent*     aChild,
diff --git a/layout/html/base/src/nsBlockFrame.h b/layout/html/base/src/nsBlockFrame.h
index d4d98fddd169..67fa31dd6369 100644
--- a/layout/html/base/src/nsBlockFrame.h
+++ b/layout/html/base/src/nsBlockFrame.h
@@ -188,12 +188,6 @@ public:
     */
   nsIFrame* GetTopBlockChild();
 
-  /** Place the floaters in the spacemanager for all lines in this block.
-    * recursively adds floaters in child blocks of this frame.
-    */
-  nsresult UpdateSpaceManager(nsIPresContext* aPresContext,
-                              nsSpaceManager* aSpaceManager);
-
   // returns true on success and false if aFoundLine is set to end_lines()
   PRBool FindLineFor(nsIFrame* aFrame,
                      PRBool* aIsFloaterResult,
diff --git a/layout/html/base/src/nsBlockReflowState.cpp b/layout/html/base/src/nsBlockReflowState.cpp
index da944f5f882f..174fbb4608c9 100644
--- a/layout/html/base/src/nsBlockReflowState.cpp
+++ b/layout/html/base/src/nsBlockReflowState.cpp
@@ -474,6 +474,14 @@ nsBlockReflowState::ReconstructMarginAbove(nsLineList::iterator aLine)
   }
 }
 
+/**
+ * Restore information about floaters into the space manager for an
+ * incremental reflow, and simultaneously push the floaters by
+ * |aDeltaY|, which is the amount |aLine| was pushed relative to its
+ * parent.  The recovery of state is one of the things that makes
+ * incremental reflow O(N^2) and this state should really be kept
+ * around, attached to the frame tree.
+ */
 void
 nsBlockReflowState::RecoverFloaters(nsLineList::iterator aLine,
                                     nscoord aDeltaY)
@@ -481,25 +489,26 @@ nsBlockReflowState::RecoverFloaters(nsLineList::iterator aLine,
   if (aLine->HasFloaters()) {
     // Place the floaters into the space-manager again. Also slide
     // them, just like the regular frames on the line.
-    nsRect r;
     nsFloaterCache* fc = aLine->GetFirstFloater();
     while (fc) {
-      fc->mRegion.y += aDeltaY;
-      fc->mCombinedArea.y += aDeltaY;
       nsIFrame* floater = fc->mPlaceholder->GetOutOfFlowFrame();
-      floater->GetRect(r);
-      floater->MoveTo(mPresContext, r.x, r.y + aDeltaY);
+      if (aDeltaY != 0) {
+        fc->mRegion.y += aDeltaY;
+        fc->mCombinedArea.y += aDeltaY;
+        nsPoint p;
+        floater->GetOrigin(p);
+        floater->MoveTo(mPresContext, p.x, p.y + aDeltaY);
+      }
 #ifdef DEBUG
       if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisySpaceManager) {
         nscoord tx, ty;
         mSpaceManager->GetTranslation(tx, ty);
         nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
-        printf("RecoverState: txy=%d,%d (%d,%d) ",
+        printf("RecoverFloaters: txy=%d,%d (%d,%d) ",
                tx, ty, mSpaceManagerX, mSpaceManagerY);
         nsFrame::ListTag(stdout, floater);
-        printf(" r.y=%d aDeltaY=%d (sum=%d) region={%d,%d,%d,%d}\n",
-               r.y, aDeltaY, r.y + aDeltaY,
-               fc->mRegion.x, fc->mRegion.y,
+        printf(" aDeltaY=%d region={%d,%d,%d,%d}\n",
+               aDeltaY, fc->mRegion.x, fc->mRegion.y,
                fc->mRegion.width, fc->mRegion.height);
       }
 #endif
@@ -511,15 +520,17 @@ nsBlockReflowState::RecoverFloaters(nsLineList::iterator aLine,
     nsBlockFrame *kid = nsnull;
     aLine->mFirstChild->QueryInterface(kBlockFrameCID, (void**)&kid);
     if (kid) {
-      nsRect kidRect;
-      kid->GetRect(kidRect);
-      mSpaceManager->Translate(kidRect.x, kidRect.y);
+      nscoord kidx = kid->mRect.x, kidy = kid->mRect.y;
+      mSpaceManager->Translate(kidx, kidy);
       for (nsBlockFrame::line_iterator line = kid->begin_lines(),
                                    line_end = kid->end_lines();
            line != line_end;
            ++line)
-        RecoverFloaters(line, aDeltaY);
-      mSpaceManager->Translate(-kidRect.x, -kidRect.y);
+        // Pass 0, not the real DeltaY, since these floaters aren't
+        // moving relative to their parent block, only relative to
+        // the space manager.
+        RecoverFloaters(line, 0);
+      mSpaceManager->Translate(-kidx, -kidy);
     }
   }
 }