DrawText in tab control

This one's embarrassingly simple, but how do I go about disabling a DrawText command in a tab control? The usual disable=(tab!=n) doesn't work with DrawText. I suspect it's to do with the /W=winName option to DrawText, but I can't find a clear example of the use of subwindow names in tab controls. Can anyone help out with either a quick example or a pointer to the documentation I should be reading?

Thanks in advance...