For once!
For once we -- that's the Krita team -- hoped to be first with a feature. After considerable discussion, we made a design for Krita 2.0 that allows users to attach any number of filters associated with a mask to a layer to have life filtering of the layer contents. I'm implementing that stuff right now (well, I'm waiting for Krita to compile, but that's immaterial). Read all about it on the wiki -- and I bet Adobe reads our wiki, too because they've got that feature, too!. Still, it has one advantage: our implementation will be familiar to Photoshop users, and that alone will surely save us from a ton of bug reports.
Of course, they didn't steal it. Their implementation will be better than ours, sure. And they will have started ages ago. But still. It rankles! It was something we thought up ourselves. Innovative-like.