diff --git a/src/frontends/qt4/Dialogs.cpp b/src/frontends/qt4/Dialogs.cpp
index c98f957fcc..4fde46988b 100644
--- a/src/frontends/qt4/Dialogs.cpp
+++ b/src/frontends/qt4/Dialogs.cpp
@@ -35,11 +35,6 @@
 #include "TocWidget.h"
 #include "GuiURL.h"
 
-#ifdef HAVE_LIBAIKSAURUS
-#include "ControlThesaurus.h"
-#include "GuiThesaurus.h"
-#endif
-
 // Uncomment this if you prefer dock widget
 //#define USE_DOCK_WIDGET
 
@@ -220,7 +215,7 @@ Dialog * Dialogs::build(string const & name)
 		return createGuiTexInfo(lyxview_);
 #ifdef HAVE_LIBAIKSAURUS
 	if (name == "thesaurus")
-		return new GuiThesaurusDialog(lyxview_);
+		return createGuiThesaurus(lyxview_);
 #endif
 	if (name == "toc") {
 #ifdef Q_WS_MACX
diff --git a/src/frontends/qt4/GuiThesaurus.cpp b/src/frontends/qt4/GuiThesaurus.cpp
index de513e6968..9daa18aeed 100644
--- a/src/frontends/qt4/GuiThesaurus.cpp
+++ b/src/frontends/qt4/GuiThesaurus.cpp
@@ -12,7 +12,6 @@
 
 #include "GuiThesaurus.h"
 
-#include "ControlThesaurus.h"
 #include "qt_helpers.h"
 #include "debug.h"
 
@@ -23,18 +22,21 @@
 #include <QTreeWidget>
 #include <QTreeWidgetItem>
 
+#include "lyxfind.h"
+#include "FuncRequest.h"
+
 using std::string;
 
 
 namespace lyx {
 namespace frontend {
 
-GuiThesaurusDialog::GuiThesaurusDialog(LyXView & lv)
-	: GuiDialog(lv, "thesaurus")
+GuiThesaurus::GuiThesaurus(LyXView & lv)
+	: GuiDialog(lv, "thesaurus"), Controller(this)
 {
 	setupUi(this);
 	setViewTitle(_("Thesaurus"));
-	setController(new ControlThesaurus(*this));
+	setController(this, false);
 
 	meaningsTV->setColumnCount(1);
 	meaningsTV->header()->hide();
@@ -43,8 +45,8 @@ GuiThesaurusDialog::GuiThesaurusDialog(LyXView & lv)
 		this, SLOT(slotClose()));
 	connect(replaceED, SIGNAL(returnPressed()),
 		this, SLOT(replaceClicked()));
-	connect(replaceED, SIGNAL(textChanged(const QString &)),
-		this, SLOT(change_adaptor() ) );
+	connect(replaceED, SIGNAL(textChanged(QString)),
+		this, SLOT(change_adaptor()));
 	connect(entryED, SIGNAL(returnPressed()),
 		this, SLOT(entryChanged()));
 	connect(replacePB, SIGNAL(clicked()),
@@ -64,34 +66,29 @@ GuiThesaurusDialog::GuiThesaurusDialog(LyXView & lv)
 }
 
 
-ControlThesaurus & GuiThesaurusDialog::controller()
-{
-	return static_cast<ControlThesaurus &>(GuiDialog::controller());
-}
-
-void GuiThesaurusDialog::change_adaptor()
+void GuiThesaurus::change_adaptor()
 {
 	changed();
 }
 
 
-void GuiThesaurusDialog::closeEvent(QCloseEvent * e)
+void GuiThesaurus::closeEvent(QCloseEvent * e)
 {
 	slotClose();
 	GuiDialog::closeEvent(e);
 }
 
 
-void GuiThesaurusDialog::entryChanged()
+void GuiThesaurus::entryChanged()
 {
 	updateLists();
 }
 
 
-void GuiThesaurusDialog::selectionChanged()
+void GuiThesaurus::selectionChanged()
 {
 	int const col = meaningsTV->currentColumn();
-	if (col < 0 || controller().isBufferReadonly())
+	if (col < 0 || isBufferReadonly())
 		return;
 
 	replaceED->setText(meaningsTV->currentItem()->text(col));
@@ -100,13 +97,13 @@ void GuiThesaurusDialog::selectionChanged()
 }
 
 
-void GuiThesaurusDialog::itemClicked(QTreeWidgetItem * /*item*/, int /*col*/)
+void GuiThesaurus::itemClicked(QTreeWidgetItem * /*item*/, int /*col*/)
 {
 	selectionChanged();
 }
 
 
-void GuiThesaurusDialog::selectionClicked(QTreeWidgetItem * item, int col)
+void GuiThesaurus::selectionClicked(QTreeWidgetItem * item, int col)
 {
 	entryED->setText(item->text(col));
 	selectionChanged();
@@ -114,12 +111,12 @@ void GuiThesaurusDialog::selectionClicked(QTreeWidgetItem * item, int col)
 }
 
 
-void GuiThesaurusDialog::updateLists()
+void GuiThesaurus::updateLists()
 {
 	meaningsTV->clear();
 	meaningsTV->setUpdatesEnabled(false);
 
-	Thesaurus::Meanings meanings = controller().getMeanings(qstring_to_ucs4(entryED->text()));
+	Thesaurus::Meanings meanings = getMeanings(qstring_to_ucs4(entryED->text()));
 
 	for (Thesaurus::Meanings::const_iterator cit = meanings.begin();
 		cit != meanings.end(); ++cit) {
@@ -138,19 +135,60 @@ void GuiThesaurusDialog::updateLists()
 }
 
 
-void GuiThesaurusDialog::updateContents()
+void GuiThesaurus::updateContents()
 {
-	entryED->setText(toqstr(controller().text()));
+	entryED->setText(toqstr(text_));
 	replaceED->setText("");
 	updateLists();
 }
 
 
-void GuiThesaurusDialog::replaceClicked()
+void GuiThesaurus::replaceClicked()
 {
-	controller().replace(qstring_to_ucs4(replaceED->text()));
+	replace(qstring_to_ucs4(replaceED->text()));
 }
 
+
+bool GuiThesaurus::initialiseParams(string const & data)
+{
+	text_ = from_utf8(data);
+	return true;
+}
+
+
+void GuiThesaurus::clearParams()
+{
+	text_.erase();
+}
+
+
+void GuiThesaurus::replace(docstring const & newstr)
+{
+	/* FIXME: this is not suitable ! We need to have a "lock"
+	 * on a particular charpos in a paragraph that is broken on
+	 * deletion/change !
+	 */
+	docstring const data =
+		replace2string(text_, newstr,
+				     true,  // case sensitive
+				     true,  // match word
+				     false, // all words
+				     true); // forward
+	dispatch(FuncRequest(LFUN_WORD_REPLACE, data));
+}
+
+
+Thesaurus::Meanings const & GuiThesaurus::getMeanings(docstring const & str)
+{
+	if (str != laststr_)
+		meanings_ = thesaurus.lookup(str);
+	return meanings_;
+}
+
+
+Dialog * createGuiThesaurus(LyXView & lv) { return new GuiThesaurus(lv); }
+
+
 } // namespace frontend
 } // namespace lyx
 
diff --git a/src/frontends/qt4/GuiThesaurus.h b/src/frontends/qt4/GuiThesaurus.h
index 297e20daf2..3e07f80eec 100644
--- a/src/frontends/qt4/GuiThesaurus.h
+++ b/src/frontends/qt4/GuiThesaurus.h
@@ -13,7 +13,7 @@
 #define GUITHESAURUS_H
 
 #include "GuiDialog.h"
-#include "ControlThesaurus.h"
+#include "Thesaurus.h"
 #include "ui_ThesaurusUi.h"
 
 class QTreeWidgetItem;
@@ -21,12 +21,12 @@ class QTreeWidgetItem;
 namespace lyx {
 namespace frontend {
 
-class GuiThesaurusDialog : public GuiDialog, public Ui::ThesaurusUi
+class GuiThesaurus : public GuiDialog, public Ui::ThesaurusUi, public Controller
 {
 	Q_OBJECT
 
 public:
-	GuiThesaurusDialog(LyXView & lv);
+	GuiThesaurus(LyXView & lv);
 
 private Q_SLOTS:
 	void change_adaptor();
@@ -39,11 +39,38 @@ private Q_SLOTS:
 private:
 	void closeEvent(QCloseEvent * e);
 	/// parent controller
-	ControlThesaurus & controller();
+	Controller & controller() { return *this; }
 	/// update
 	void updateContents();
 	///
 	void updateLists();
+	///
+	bool initialiseParams(std::string const & data);
+	///
+	void clearParams();
+	///
+	void dispatchParams() {}
+	///
+	bool isBufferDependent() const { return true; }
+
+	/// replace the particular string
+	void replace(docstring const & newstr);
+
+	/// get meanings
+	Thesaurus::Meanings const & getMeanings(docstring const & str);
+
+private:
+	/// last string looked up
+	docstring laststr_;
+
+	/// entries for last string
+	Thesaurus::Meanings meanings_;
+
+	/// original string
+	docstring text_;
+
+	/// not needed.
+	void apply() {}
 };
 
 } // namespace frontend