diff --git a/src/frontends/qt4/GuiView.cpp b/src/frontends/qt4/GuiView.cpp
index 735919925f..37d7cf4437 100644
--- a/src/frontends/qt4/GuiView.cpp
+++ b/src/frontends/qt4/GuiView.cpp
@@ -1022,7 +1022,7 @@ bool GuiView::focusNextPrevChild(bool /*next*/)
 }
 
 
-bool GuiView::busy()
+bool GuiView::busy() const
 {
 	return busy_;
 }
diff --git a/src/frontends/qt4/GuiView.h b/src/frontends/qt4/GuiView.h
index 72a53dbdc6..f1612b99d7 100644
--- a/src/frontends/qt4/GuiView.h
+++ b/src/frontends/qt4/GuiView.h
@@ -80,7 +80,7 @@ public:
 	///
 	void setBusy(bool);
 	/// are we busy ?
-	bool busy();
+	bool busy() const;
 
 	/// \name Generic accessor functions
 	//@{