diff --git a/src/mac/carbon/textctrl.cpp b/src/mac/carbon/textctrl.cpp
index 0e5bf76b19..599dc75b6b 100644
--- a/src/mac/carbon/textctrl.cpp
+++ b/src/mac/carbon/textctrl.cpp
@@ -56,6 +56,8 @@
 #include <Scrap.h>
 #endif
 
+// if this is set to 1 then under OSX 10.2 the 'classic' MLTE implementation will be used
+// if set to 0 then the unicode textctrl will be used
 #ifndef wxMAC_AWAYS_USE_MLTE
 #define wxMAC_AWAYS_USE_MLTE 1
 #endif