In the Data Frame properties under the Frame tab there's an option for Rounding which will round the corners of your data frame.
I have a map layout where several data frames are used as insets. I wanted them rounded to match my main dataframe which is also rounded. But when I export this to PDF the square corners are still visible and in white against a dark backdrop.
I tried printing it straight from ArcMap and the squared corners are still there. Anyone come across this able to fix it?
I'm in ArcMap 9.3.1
I tried a smaller sample this morning and for some reason this behaviour only affects one of my inset data frames, and not both.