John,

>Are you using INTL? Can I ask you some questions?

Yes.

>In INTL, do you need to set the language everytime in form.init() in situation above? Or, INTL will handle for you?

INTL will handle this. Basically, what it takes to change the language on the fly is something like this:

*-- set new language
_SCREEN.oINTL.SetLanguage("French")

*-- localize all active forms
FOR EACH oForm IN _SCREEN.Forms
   _SCREEN.oINTL.Localize(oForm)
ENDFOR

*-- localize menu
DO YourMenu.mpr

>Does INTL convert caption of ActiveX control?
Sorry, I don't know.

Did you check the INTL site? It contains a lot of useful information concerning localization.