i'm not sure how you can do it in DBP without a DLL plugin i'm afraid, however in DB it is a simply case of minimising and taking a snapshot of the back buffer.
Then saving that to a memblock/array so that you can then use the pixels as a background bitmap for the area the window is currently covering.
It doesn't work as well in DBP because everything turns exclusive, backbuffer/window properties/etc...
which is rather annoying.
Short answer is really without having the ability to take a screenshot of your desktop without the window, you can't do it.
There maybe a way using the Windows System DLLs - but for the life of me i can't think what it is.

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