Prevent redirect when dragging images and links into designMode IFrame of HTA?

Question

I have an HTA that contains two IFrames.  One is in designMode and the other acts as a browser-in-a-browser.  The aim of my application is to allow users to drag contents into the designMode IFrame and save what is dragged in there.  Everything works fine except in two cases:  When the user drags an image or link WITHOUT selecting them (ie, not highlighted), the entire HTA frame is redirected to show the image or the link's target page, respectively (same behavior as dragging an image or HTML file from your desktop into the browser). 

Is there any way to prevent this behavior?

Thanks.