diff --git a/src/common/dcbase.cpp b/src/common/dcbase.cpp
index cca78bab32..9cffc3896a 100644
--- a/src/common/dcbase.cpp
+++ b/src/common/dcbase.cpp
@@ -653,7 +653,7 @@ void wxDCBase::DrawLabel(const wxString& text,
         }
         else // not end of line
         {
-            if ( pc - text.begin() == indexAccel )
+            if ( pc - text.begin() == (size_t)indexAccel )
             {
                 // remeber to draw underscore here
                 GetTextExtent(curLine, &startUnderscore, NULL);