Camerabits did state in their press release for future PM 5.0 (in the works) version, Preview and Contact sheet window are going to be non-modal, meaning in v5 you would be able to move either to different screen and work with both (as I understand it). Fullscreen would be pretty nice icing on the cake some time down the road, but I don't know how much reworking the PM's code would need. So far, I have simply put PM into it's own space rearranged alongside Photoshop, but isnce Photoshop doesn't support Apple's fullscreen mode (or even Apple's Expose/Mission Control), it has few quirks. Since PM and PS launches at start instantly (using SSD <g>), it's always at the space I set it. Only in Fullscreen mode the Dock/Menubar is hidden which is nice for previewing...