diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index ea1168b684..c6ce92aa97 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -427,7 +427,22 @@ Buffer::~Buffer()
 
 Buffer * Buffer::clone() const
 {
+	BufferMap bufmap;
+	masterBuffer()->clone(bufmap);
+	BufferMap::iterator it = bufmap.find(this);
+	LASSERT(it != bufmap.end(), return 0);
+	return it->second;
+}
+
+
+void Buffer::clone(BufferMap & bufmap) const
+{
+	// have we already been cloned?
+	if (bufmap.find(this) != bufmap.end())
+		return;
+
 	Buffer * buffer_clone = new Buffer(fileName().absFileName(), false, this);
+	bufmap[this] = buffer_clone;
 	buffer_clone->d->macro_lock = true;
 	buffer_clone->d->children_positions.clear();
 	// FIXME (Abdel 09/01/2010): this is too complicated. The whole children_positions and
@@ -440,7 +455,12 @@ Buffer * Buffer::clone() const
 		DocIterator dit = it->second.clone(buffer_clone);
 		dit.setBuffer(buffer_clone);
 		Buffer * child = const_cast<Buffer *>(it->first);
-		Buffer * child_clone = child->clone();
+
+		child->clone(bufmap);
+		BufferMap::iterator it = bufmap.find(child);
+		LASSERT(it != bufmap.end(), continue);
+		Buffer * child_clone = it->second;
+
 		Inset * inset = dit.nextInset();
 		LASSERT(inset && inset->lyxCode() == INCLUDE_CODE, continue);
 		InsetInclude * inset_inc = static_cast<InsetInclude *>(inset);
@@ -449,7 +469,7 @@ Buffer * Buffer::clone() const
 		buffer_clone->setChild(dit, child_clone);
 	}
 	buffer_clone->d->macro_lock = false;
-	return buffer_clone;
+	return;
 }
 
 
diff --git a/src/Buffer.h b/src/Buffer.h
index b5c34b3a08..9701f31913 100644
--- a/src/Buffer.h
+++ b/src/Buffer.h
@@ -211,6 +211,10 @@ public:
 	int readHeader(Lexer & lex);
 
 private:
+	///
+	typedef std::map<Buffer const *, Buffer *> BufferMap;
+	///
+	void clone(BufferMap &) const;
 	/// save timestamp and checksum of the given file.
 	void saveCheckSum() const;	
 	/// read a new file
diff --git a/src/frontends/qt4/GuiView.cpp b/src/frontends/qt4/GuiView.cpp
index 89a00c6609..97d3204917 100644
--- a/src/frontends/qt4/GuiView.cpp
+++ b/src/frontends/qt4/GuiView.cpp
@@ -2944,7 +2944,11 @@ docstring GuiView::GuiViewPrivate::runAndDestroy(const T& func, Buffer const * o
 				buffer->params().maintain_unincluded_children
 				&& !buffer->params().getIncludedChildren().empty();
 	bool const success = func(format, update_unincluded);
-	delete buffer;
+
+	// the cloning operation will have produced a clone of the entire set of
+	// documents, starting from the master. so we must delete those.
+	Buffer * mbuf = const_cast<Buffer *>(buffer->masterBuffer());
+	delete mbuf;
 	busyBuffers.remove(orig);
 	if (msg == "preview") {
 		return success