<p>Microsoft decided to change the way the 2010 viewer worked compared to all the previous versions. This means that is more difficult to work with. It looks as if they are intentionally making it harder for applications like OpenLP to use, as they obviously want people to buy the full Office suite! Unfortunately it would require more time than I have to try and figure out how to reliably control it, if indeed it can be.</p><p>You may well find the 2010 pptx's work fine with the 2007 viewer anyway.</p>