Selection borders appearing on click in latest Firefox?

Hello!

On my website, I have flash videos that are positioned on edges of the site, which resize to scale depending on browser resolution. This used to be fine across all browers, but in the latest version of Firefox I’ve come across an issue. When the site loads, everything looks great. However, when clicking on some the flash videos that are used for navigation, scrollbars appear around the site, which I do not – not just because I don’t like the look of it, but also because it causes everything to resize, sometimes causing the links to move out from under the cursor.

I first thought of simply adding “overflow: hidden” into the body tag of the css for the site. I even tried it out. It worked, but then I came across a new problem: the site won’t be browsable at very, very low resolutions. (There is a content div in the middle of some pages which uses a scrollbar, and if that scrollbar were to load outside of the itty bitty browser window, there would be no way to scroll through the div’s content.) An unlikely problem to encounter, as it would require a ridiculously small browser window to be an issue, but being a perfectionist it’s a problem that I’d like to avoid nonetheless.

It appears to me that the issue of these appearing scrollbars is being caused by a 1-pixel wide, dashed “selection border” appearing around the flash videos when they are clicked on in Firefox. If you click on another part of the page outside of that flash video after this happens, then the selection border goes away and so do the scrollbars, leading everything to return to its original size.

So I believe that my question should be this: How can I make it so this “selection border” stops appearing around my flash videos when they are clicked on in the newest version of Firefox?