It took me a while to figure out how to prevent this �loss � and the associated frustrations.

When you paste the slide, a (very) small box appears briefly above or below the copied slide.  It �s the �Paste Option � box. When you click on the arrow, you get a choice to "use the destination theme" or to "keep source formatting".  Choose the latter, and the backgrounds stays as it was in the original file.

No more headaches and/or frustrations!

Just remember: computers are a male invention.  Faaaaar from perfect :-)

Yours in teaching,

Peter