iframe does not show up in Design mode

[Ellmura]

Hi, hope you can help with my problem.

I've inserted some Amazon affiliate ads coded as iframes on my website. The problem is that they don't show up in Design mode in Dreamweaver MX. Not even a placeholder or missing object icon to indicate where they are. But the ads show up when I view them in any browser.

Here's an example of the iframe code.

<iframe src="

http://rcm.amazon.com/e/cm?t=oobarg...arrypotter&banner=1J0FZGQYRKKN19GRRSG2&f=ifr"

width="468" height="60" scrolling="no" border="0" marginwidth="0" style="border:none;" frameborder="0"></iframe>

I have no idea why this is happening. Anyone know?

Thanks.