diff --git a/src/misc/TextHandler.h b/src/misc/TextHandler.h

index b2fc8f6..66772eb 100644

--- a/src/misc/TextHandler.h

+++ b/src/misc/TextHandler.h

@@ -14,7 +14,7 @@ using namespace std;

 struct stringLessThan

 {

-	bool operator()(const char *s1, const char *s2)

+	bool operator()(const char *s1, const char *s2) const

 	{

 		return strcmp(s1, s2) < 0;

 	}