diff --git a/src/slic3r/GUI/wxExtensions.cpp b/src/slic3r/GUI/wxExtensions.cpp
index 1ae0448f42..547975c37e 100644
--- a/src/slic3r/GUI/wxExtensions.cpp
+++ b/src/slic3r/GUI/wxExtensions.cpp
@@ -1384,6 +1384,8 @@ wxString PrusaDoubleSlider::get_label(const SelectedSlider& selection) const
 
     if (m_label_koef == 1.0 && m_values.empty())
         return wxString::Format("%d", value);
+    if (value >= m_values.size())
+        return "ErrVal";
 
     const wxString str = m_values.empty() ? 
                          wxNumberFormatter::ToString(m_label_koef*value, 2, wxNumberFormatter::Style_None) :