>One minute I'm tiptoeing through the tulips, the next I'm mincing through the
>mines. I thought copybits took care of differences between the source gworld
>and the screen - whatever the definition of the screen.

It does. CopyBits will automatically convert pixels from the source bit 
depth to the destination bit depth.

The problems I assume Lucy is referring to are mainly cosmetic. Consider:
- Your app checks the monitor depth before drawing a window. If 8 bit or 
higher, your app draws a gloriously colourful layout. If below 8 bit, 
your app draws a plain, boring monochrome layout.
- User launches app with monitor set to 4-bit color.
- App draws plain, boring image into the window.
- User changes monitor bit depth to 8-bit color.
- App refreshes window using the plain, boring image saved in the GWorld, 
never noticing that it could instead draw the gloriously colourful 8-bit 
image.

The way around this is to compare the monitor bit depth against your 
GWorld's bit depth at every refresh. If the two differ, redraw your 
GWorld first.

Or just don't include a fancy colour version of your window layout. :-)

-Mars