diff --git a/interface/wx/grid.h b/interface/wx/grid.h
index 677af21bf0..5ebbcba37c 100644
--- a/interface/wx/grid.h
+++ b/interface/wx/grid.h
@@ -461,7 +461,7 @@ public:
         Draws the part of the cell not occupied by the control: the base class
         version just fills it with background colour from the attribute.
     */
-    virtual void PaintBackground(wxDC& dc, const wxRect& rectCell, wxGridCellAttr& attr);
+    virtual void PaintBackground(wxDC& dc, const wxRect& rectCell, const wxGridCellAttr& attr);
 
     /**
         Reset the value in the control back to its starting value.