diff --git a/src/frontends/Application.h b/src/frontends/Application.h
index c12d8a938d..0bba5cea55 100644
--- a/src/frontends/Application.h
+++ b/src/frontends/Application.h
@@ -239,6 +239,14 @@ public:
 	/// Handle a accented char key sequence
 	/// FIXME: this is only needed for LFUN_ACCENT_* in Text::dispatch()
 	virtual void handleKeyFunc(FuncCode action) = 0;
+
+	/// Start a long operation with some cancel possibility (button or ESC)
+	virtual void startLongOperation() = 0;
+	/// This needs to be periodically called to avoid freezing the GUI
+	virtual bool longOperationCancelled() = 0;
+	/// Stop the long operation mode (i.e., release the GUI)
+	virtual void stopLongOperation() = 0;
+
 };
 
 /// Return the list of loadable formats.
diff --git a/src/frontends/qt4/FindAndReplace.cpp b/src/frontends/qt4/FindAndReplace.cpp
index 1d2a81d4f6..82844bcbf9 100644
--- a/src/frontends/qt4/FindAndReplace.cpp
+++ b/src/frontends/qt4/FindAndReplace.cpp
@@ -294,6 +294,8 @@ bool FindAndReplaceWidget::findAndReplaceScope(FindAndReplaceOptions & opt, bool
 	oss << opt;
 	FuncRequest cmd(LFUN_WORD_FINDADV, from_utf8(oss.str()));
 
+	view_.message(_("Advanced search started: please wait . . ."));
+	theApp()->startLongOperation();
 	view_.setBusy(true);
 	if (opt.scope == FindAndReplaceOptions::S_ALL_MANUALS) {
 		vector<string> const & v = allManualsFiles();
@@ -301,7 +303,9 @@ bool FindAndReplaceWidget::findAndReplaceScope(FindAndReplaceOptions & opt, bool
 			FileName const & fname = FileName(*v.begin());
 			if (!theBufferList().exists(fname)) {
 				guiApp->currentView()->setBusy(false);
+				theApp()->stopLongOperation();
 				guiApp->currentView()->loadDocument(fname, false);
+				theApp()->startLongOperation();
 				guiApp->currentView()->setBusy(true);
 			}
 			buf = theBufferList().getBuffer(fname);
@@ -327,10 +331,19 @@ bool FindAndReplaceWidget::findAndReplaceScope(FindAndReplaceOptions & opt, bool
 			if (replace_all)
 				continue;
 			view_.setBusy(false);
+			theApp()->stopLongOperation();
 			return true;
 		} else if (replace_all)
 			bv->clearSelection();
 
+		if (theApp()->longOperationCancelled()) {
+			// Search aborted by user
+			view_.message(_("Advanced search cancelled by user"));
+			view_.setBusy(false);
+			theApp()->stopLongOperation();
+			return false;
+		}
+
 		// No match found in current buffer (however old selection might have been replaced)
 		// select next buffer in scope, if any
 		bool const prompt = nextPrevBuffer(buf, opt);
@@ -341,9 +354,11 @@ bool FindAndReplaceWidget::findAndReplaceScope(FindAndReplaceOptions & opt, bool
 				break;
 			docstring q = getQuestionString(opt);
 			view_.setBusy(false);
+			theApp()->stopLongOperation();
 			wrap_answer = frontend::Alert::prompt(
 				_("Wrap search?"), q,
 				0, 1, _("&Yes"), _("&No"));
+			theApp()->startLongOperation();
 			view_.setBusy(true);
 			if (wrap_answer == 1)
 				break;
@@ -373,6 +388,7 @@ bool FindAndReplaceWidget::findAndReplaceScope(FindAndReplaceOptions & opt, bool
 		cur_orig.pos() = cur_orig.lastpos();
 	bv->cursor().setCursor(cur_orig);
 	view_.setBusy(false);
+	theApp()->stopLongOperation();
 	return false;
 }
 
diff --git a/src/frontends/qt4/GuiApplication.cpp b/src/frontends/qt4/GuiApplication.cpp
index a49a995210..0f6c38fb83 100644
--- a/src/frontends/qt4/GuiApplication.cpp
+++ b/src/frontends/qt4/GuiApplication.cpp
@@ -80,12 +80,14 @@
 #include <QClipboard>
 #include <QDateTime>
 #include <QDir>
+#include <QEvent>
 #include <QEventLoop>
 #include <QFileOpenEvent>
 #include <QFileInfo>
 #include <QHash>
 #include <QIcon>
 #include <QImageReader>
+#include <QKeyEvent>
 #include <QLocale>
 #include <QLibraryInfo>
 #include <QList>
@@ -98,6 +100,7 @@
 #include <QRegExp>
 #include <QSessionManager>
 #include <QSettings>
+#include <QShowEvent>
 #include <QSocketNotifier>
 #include <QSortFilterProxyModel>
 #include <QStandardItemModel>
@@ -675,6 +678,43 @@ public:
 
 #endif // Q_WS_WIN
 
+
+/// Allows to check whether ESC was pressed during a long operation
+class KeyChecker : public QObject {
+private:
+	bool pressed_;
+public:
+	KeyChecker() {
+		pressed_ = false;
+	}
+	void start() {
+		QCoreApplication::instance()->installEventFilter(this);
+		pressed_ = false;
+	}
+	void stop() {
+		QCoreApplication::instance()->removeEventFilter(this);
+	}
+	bool pressed() {
+		QCoreApplication::processEvents();
+		return pressed_;
+	}
+	bool eventFilter(QObject *obj, QEvent *event) {
+		LYXERR(Debug::ACTION, "Event Type: " << event->type());
+		switch (event->type()) {
+		case QEvent::Show:
+		case QEvent::Hide:
+		case QEvent::Resize:
+			return QObject::eventFilter(obj, event);
+		default:
+			QKeyEvent *keyEvent = dynamic_cast<QKeyEvent*>(event);
+			if (keyEvent && keyEvent->key() == Qt::Key_Escape)
+				pressed_ = true;
+			return true;
+		}
+	}
+};
+
+
 ////////////////////////////////////////////////////////////////////////
 // GuiApplication::Private definition and implementation.
 ////////////////////////////////////////////////////////////////////////
@@ -752,6 +792,9 @@ struct GuiApplication::Private
 	/// WMF Mime handler for Windows clipboard.
 	QWindowsMimeMetafile * wmf_mime_;
 #endif
+
+	/// Allows to check whether ESC was pressed during a long operation
+	KeyChecker key_checker_;
 };
 
 
@@ -2529,6 +2572,21 @@ void GuiApplication::onLastWindowClosed()
 }
 
 
+void GuiApplication::startLongOperation() {
+	d->key_checker_.start();
+}
+
+
+bool GuiApplication::longOperationCancelled() {
+	return d->key_checker_.pressed();
+}
+
+
+void GuiApplication::stopLongOperation() {
+	d->key_checker_.stop();
+}
+
+
 ////////////////////////////////////////////////////////////////////////
 //
 // X11 specific stuff goes here...
diff --git a/src/frontends/qt4/GuiApplication.h b/src/frontends/qt4/GuiApplication.h
index d1a10784b8..b4c7615749 100644
--- a/src/frontends/qt4/GuiApplication.h
+++ b/src/frontends/qt4/GuiApplication.h
@@ -169,6 +169,13 @@ public:
 	///		not the current buffer
 	void gotoBookmark(unsigned int idx, bool openFile, bool switchToBuffer);
 
+	/// Start a long operation with some cancel possibility (button or ESC)
+	void startLongOperation();
+	/// This needs to be periodically called to avoid freezing the GUI
+	bool longOperationCancelled();
+	/// Stop the long operation mode (i.e., release the GUI)
+	void stopLongOperation();
+
 private Q_SLOTS:
 	///
 	void execBatchCommands();
diff --git a/src/lyxfind.cpp b/src/lyxfind.cpp
index b67f915d7c..f90e530d82 100644
--- a/src/lyxfind.cpp
+++ b/src/lyxfind.cpp
@@ -1133,12 +1133,12 @@ int findForwardAdv(DocIterator & cur, MatchStringAdv & match)
 {
 	if (!cur)
 		return 0;
-	while (cur) {
+	while (!theApp()->longOperationCancelled() && cur) {
 		LYXERR(Debug::FIND, "findForwardAdv() cur: " << cur);
 		int match_len = match(cur, -1, false);
 		LYXERR(Debug::FIND, "match_len: " << match_len);
 		if (match_len) {
-			for (; cur; cur.forwardPos()) {
+			for (; !theApp()->longOperationCancelled() && cur; cur.forwardPos()) {
 				LYXERR(Debug::FIND, "Advancing cur: " << cur);
 				int match_len = match(cur);
 				LYXERR(Debug::FIND, "match_len: " << match_len);
@@ -1235,7 +1235,7 @@ int findBackwardsAdv(DocIterator & cur, MatchStringAdv & match) {
 		else
 			cur.backwardPos();
 		pit_changed = true;
-	} while (true);
+	} while (!theApp()->longOperationCancelled());
 	return 0;
 }