This is actually a common misconception. Encore will render the motion menus during the build process whether you selected "Render > Motion Menus" or not.
In most cases, it will re-render them during the build process even if you have already rendered them by selecting the "Render > Motion Menus", making it completely pointless unless you just want to preview it.
In fact, I find the preview not very accurate either (particularly with Blu-ray), so I usually skip the preview, don't even bother clicking "render > motion menus", go straight to building an image, mount it to a drive, then play it back using a software dvd player.
Jon Geddes
Providing the Best Motion Menu Templates Available for Video Production
www.precomposed.com
