GIMP qeustion - copying from one window to another

[Giant_Robot]

I've looked everywhere for instructions on how to do this, but I've come up empty handed.

I need to be able to copy part of one image to another. I believe the Buffer may be used to transfer between windows, but none of the tutorials I've seen explain how to do this. I assume it's fairly simple, but it's driving me nuts!

[Uranus]

I think this should work as easy as copy-paste - don't remember having any problems with that. Are you sure that you're copying from the layer that holds the image and pasting to a visible layer?
Sam