In older versions of Flexi, PDFs may not render correctly due to transparencies. In Flexi 10, you can open a "linked" PDF that allows you to do some limited editing, but that will also display as intended.
To do this, go to File > Import. Select a PDF and check the "Link" box on the right side of the dialog box.
Since you have v10, you can update for free to SAi Flexi Cloud, which includes PDF transparency improvements. Visit store.thinksai.com/update for more info!