Cabin Filter Replacement

[squeasel]

Tinkering with the X5 and decided to replace the cabin filter. I bougt a Mann filter and swapped it with what was in the car (perhaps original?). The filter that I removed has a platic border with yellow foam rubber around it. The border seems like a good idea and that it should be reusable. But the older filter seems glued on.

My question ... do I reuse the plastic border or do I just insert the new cabin filter?

Much thanks.