Thanks for your kind words!
Can you share the code you're using to declare the AlphaMask? I ran a quick test with the following code:
image radial_mask = GradientDisplayable(["#fff", "#0000"], xysize=(800, 800), kind='radial') image feniks_masked = AlphaMask("feniks", "radial_mask") default who = "feniks" image test_masked = AlphaMask("[who]", "radial_mask")
which I was able to get working in 8.1, so with luck it'll just be a declaration issue :)