Hi, I'm still stuck on this problem and can find no help in the manual.
Just to reiterate:
I have an animated window and I want to adjust the window feathering. The problem is that any changes to the edge softness is recorded in the current key-frame and doesn't change the window globally. So I can't adjust the window softness after tracking it without having to start from scratch.
The only real option I'm aware of is to go to each keyframe and make the adjustment on a keyframe by keyframe basis. If it's a circlular window, you can easily copy and paste. other than that, it's quite a bit more tedious.
No promises on this, but maybe try duplicating the node in question (by copy and pasting it into another node) feeding that as a matte into the current node, inverting it, and then adjusting the settings in the key tab. It's worth a shot.