I am using Bryce 5.5 and was going through the manual looking for something else when I stumbled on this under the heading of Customizing Bryce.
 ***"To hide the Bryce interface, press Command/Ctrl+Alt. All the palettes disappear and your image appears at the center of your workspace. Press Command/Ctrl+Alt again to display all the palettes."***My question is what is the "Command" key on a keyboard, I don't seem to have one of those. 
In Corel's original version of Bryce 5 I used to be able to do this by Ctr+tab but lost that ability by installing the 5.01 patch. I used to love this function as it would give me a full screen render while rendering and made it a lot easier when plop rendering.

P.S
In this section it also tells you how you can move the palettes around by holding down the space bar and clicking on a palette. I had forgotten all about that one.

Command = MAC

Ctrl = PC

Doh !! Shows you I've never been behind the wheel of a MAC. Ok, it doesn't seem to work then because I've tried just Cntrl+Alt and nothing happens.

and I wouldn't expect it to: Control and Alt (and Shift) keys are just modifiers. You usually need something else additional, a 'real' key. I suspect the documentation is incomplete. Perhaps a left mouse click on the background?

Th problem with this is that it doesn't always work.

I use that functionality all the time. I would use Bryce 6 more often if it had this. So I still use Bryce 5 for overall layout, then do the final renders in Bryce 6 if I need HDRI.