Sadly this is a know issue (since 8.1) with the data frame clip If you are using rasters. The data frame clip will only work if you have vector layershttp://support.esri.com/en/knowledgebase/techarticles/detail/17336The only way to fix is to:- Do not use transparent symbology, picture marker symbology nor include raster data in a data frame that obscures the layers behind it. If the data frame contains only vector data and neither transparency nor picture marker symbology, the transparency of the data frame background may be preserved.I would be interested to see if this happens when using Windows 8 as the problem is with the graphics engine which was built by Microsoft