diff --git a/modules/gui/qt4/util/input_slider.cpp b/modules/gui/qt4/util/input_slider.cpp
index ecbcd25aba32d5f934b302abf64d82f96a14d8f6..77494a62af5878bf0477eaf8b2730a38f45c9858 100644
--- a/modules/gui/qt4/util/input_slider.cpp
+++ b/modules/gui/qt4/util/input_slider.cpp
@@ -260,7 +260,7 @@ void SeekSlider::mouseMoveEvent( QMouseEvent *event )
                     if ( event->x() >= x )
                         i_selected = i + ( ( b_startsnonzero )? 1 : 0 );
                 }
-                if ( i_selected >= 0 )
+                if ( i_selected >= 0 && i_selected < points.size() )
                     chapterLabel = points.at( i_selected ).name;
         }