Different behavior for BG gradient in WD6

OK I used to be a whiz at creating BG gradients like this one before I upgraded to WD6. But today I went to try to create one and it's not working. The imported PNG gradient "section" displays in the BITMP gallery but doesn't go in as a background when I select BG.

What is going on?

Right-click your page and select 'Default Background colors' - then go to the bitmap gallery, select your bitmap and press the 'Background' button.

thanks!