eye candy impact help please

[bikerdave]

hi, i've been playing around wih impact, which i'm new to, and got a couple of results with it recently that i'd like to be able to produce again, but cant....
the filter is chrome, and i opened a new file then selected custom shape tool and put in a cross shape which appeared on a new layer as a shape. then after running the chrome filter the result filled the entire window, the chrome cross in the centre, and nice abstract chrome effect filling the rest of the frame. i also did the same thing with other shapes getting similar results.
since then i've only been getting the shape selected in chrome, the rest of the frame staying blank.
am i doing something wrong, and if so, how can i control the result?
sorry if this is a basic thing i'm missing, but i have tried. honest.
thanks for any help you can give, take care, dave.