diff --git a/common/rfb/UpdateTracker.h b/common/rfb/UpdateTracker.h
index 5b51317..8e96d55 100644
--- a/common/rfb/UpdateTracker.h
+++ b/common/rfb/UpdateTracker.h
@@ -33,9 +33,13 @@
     bool is_empty() const {
       return copied.is_empty() && changed.is_empty();
     }
+    // NOTE: We do not ever use UpdateInfo::numRects(), because Tight encoding
+    //       complicates computing the number of rectangles.
+    /*
     int numRects() const {
       return copied.numRects() + changed.numRects();
     }
+    */
   };
 
   class UpdateTracker {
@@ -59,7 +63,7 @@
     virtual void add_copied(const Region &dest, const Point &delta);
   protected:
     UpdateTracker* ut;
-    Region clipRect;
+    Rect clipRect;
   };
 
   class SimpleUpdateTracker : public UpdateTracker {
@@ -74,17 +78,12 @@
     virtual void subtract(const Region& region);
 
     // Fill the supplied UpdateInfo structure with update information
+    // FIXME: Provide getUpdateInfo() with no clipping, for better efficiency.
     virtual void getUpdateInfo(UpdateInfo* info, const Region& cliprgn);
 
     // Copy the contained updates to another tracker
     virtual void copyTo(UpdateTracker* to) const;
 
-
-    // Get the changed/copied regions
-    const Region& get_changed() const {return changed;}
-    const Region& get_copied() const {return copied;}
-    const Point& get_delta() const {return copy_delta;}
-
     // Move the entire update region by an offset
     void translate(const Point& p) {changed.translate(p); copied.translate(p);}
 
diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index bd067be..974a81e 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -568,17 +568,28 @@
 {
   if (state() != RFBSTATE_NORMAL || requested.is_empty()) return;
 
+  updates.enable_copyrect(cp.useCopyRect);
+
   server->checkUpdate();
 
+  // Get the lists of updates. Prior to exporting the data to the `update' object,
+  // getUpdateInfo() will normalize the `updates' object such way that its
+  // `changed' and `copied' regions would not intersect.
+
+  UpdateInfo update;
+  updates.getUpdateInfo(&update, requested);
+  bool needNewUpdateInfo = false;
+
   // If the previous position of the rendered cursor overlaps the source of the
   // copy, then when the copy happens the corresponding rectangle in the
   // destination will be wrong, so add it to the changed region.
 
-  if (!updates.get_copied().is_empty() && !renderedCursorRect.is_empty()) {
-    Rect bogusCopiedCursor = (renderedCursorRect.translate(updates.get_delta())
+  if (!update.copied.is_empty() && !renderedCursorRect.is_empty()) {
+    Rect bogusCopiedCursor = (renderedCursorRect.translate(update.copy_delta)
                               .intersect(server->pb->getRect()));
-    if (!updates.get_copied().intersect(bogusCopiedCursor).is_empty()) {
+    if (!update.copied.intersect(bogusCopiedCursor).is_empty()) {
       updates.add_changed(bogusCopiedCursor);
+      needNewUpdateInfo = true;
     }
   }
 
@@ -587,6 +598,7 @@
 
   if (removeRenderedCursor) {
     updates.add_changed(renderedCursorRect);
+    needNewUpdateInfo = true;
     renderedCursorRect.clear();
     removeRenderedCursor = false;
   }
@@ -596,6 +608,11 @@
   if (updates.is_empty() && !writer()->needFakeUpdate() && !drawRenderedCursor)
     return;
 
+  // The `updates' object could change, make sure we have valid update info.
+
+  if (needNewUpdateInfo)
+    updates.getUpdateInfo(&update, requested);
+
   // If the client needs a server-side rendered cursor, work out the cursor
   // rectangle.  If it's empty then don't bother drawing it, but if it overlaps
   // with the update region, we need to draw the rendered cursor regardless of
@@ -608,7 +625,7 @@
 
     if (renderedCursorRect.is_empty()) {
       drawRenderedCursor = false;
-    } else if (!updates.get_changed().union_(updates.get_copied())
+    } else if (!update.changed.union_(update.copied)
                .intersect(renderedCursorRect).is_empty()) {
       drawRenderedCursor = true;
     }
@@ -618,16 +635,15 @@
     // the same bit of screen twice, but we have the overhead of a more complex
     // region.
 
-    //if (drawRenderedCursor)
+    //if (drawRenderedCursor) {
     //  updates.subtract(renderedCursorRect);
+    //  updates.getUpdateInfo(&update, requested);
+    //}
   }
 
-  UpdateInfo update;
-  updates.enable_copyrect(cp.useCopyRect);
-  updates.getUpdateInfo(&update, requested);
   if (!update.is_empty() || writer()->needFakeUpdate() || drawRenderedCursor) {
     // Compute the number of rectangles. Tight encoder makes the things more
-    // complicated as compared to the original RealVNC.
+    // complicated as compared to the original VNC4.
     writer()->setupCurrentEncoder();
     int nRects = update.copied.numRects() + (drawRenderedCursor ? 1 : 0);
     std::vector<Rect> rects;
@@ -635,7 +651,7 @@
     update.changed.get_rects(&rects);
     for (i = rects.begin(); i != rects.end(); i++) {
       if (i->width() && i->height())
-	nRects += writer()->getNumRects(*i);
+        nRects += writer()->getNumRects(*i);
     }
     
     writer()->writeFramebufferUpdateStart(nRects);
diff --git a/common/rfb/VNCServerST.cxx b/common/rfb/VNCServerST.cxx
index cc18faa..c02c2eb 100644
--- a/common/rfb/VNCServerST.cxx
+++ b/common/rfb/VNCServerST.cxx
@@ -451,12 +451,15 @@
 
 void VNCServerST::checkUpdate()
 {
+  UpdateInfo ui;
+  comparer->getUpdateInfo(&ui, pb->getRect());
+
   bool renderCursor = needRenderedCursor();
 
-  if (comparer->is_empty() && !(renderCursor && renderedCursorInvalid))
+  if (ui.is_empty() && !(renderCursor && renderedCursorInvalid))
     return;
 
-  Region toCheck = comparer->get_changed().union_(comparer->get_copied());
+  Region toCheck = ui.changed.union_(ui.copied);
 
   if (renderCursor) {
     Rect clippedCursorRect
@@ -490,8 +493,8 @@
   std::list<VNCSConnectionST*>::iterator ci, ci_next;
   for (ci = clients.begin(); ci != clients.end(); ci = ci_next) {
     ci_next = ci; ci_next++;
-    (*ci)->add_copied(comparer->get_copied(), comparer->get_delta());
-    (*ci)->add_changed(comparer->get_changed());
+    (*ci)->add_copied(ui.copied, ui.copy_delta);
+    (*ci)->add_changed(ui.changed);
   }
 
   comparer->clear();