Image-adjustement.glsl not working with xbr-lvl3-multipass

Hello, I am trying to use the image-adjustment shader with my new favorite xbr-lvl3-multipass shader. Xbr works fine, but tweeking the parameters for image-adjustment has no effect. I can see and change the options, like contrast etc, but the picture doesn’t change. I tried changing the filter and scale to no avail. Any ideas what’s wrong?