Combinations no link


i know usually is the combinations link, in the past it´s named exceptions, at the bottom of “Global options” but when i can remember i must somehting feature enable or disable that it appears. At this moment it doesnt appears, why?

thank you very much!

O.K. i have found it, it appears when a product has added this options and in general profuct information i can choose allowed combinations or forbidden combinations.