When embedding a video on a WordPress site with a Google maps background, all other content becomes invisible on Chrome

Question

I have a problem on Google Chrome, on a WordPress site with a Google map as background: when embedding a video (any video) in a post or page, all content, including background and title, becomes invisible as soon as the map is loaded, except for the video(s). The weird part is that there was no problem before.

It most likely has something to do with the overflow and fixed position, because the problem is gone when I remove one or the other from the stylesheet, but that's not a solution.

Probably related, because it happened simultaneously: all sidebar items were gone in Opera and Chrome (didn't check IE). I moved these out of the footer, which helped, but it beats me why and I can't try the same with posts and pages.

Also new and possibly related: on the homepage, on Chrome & Opera, not FireFox, the slider (Flex) blinks on hover. Also, especially on Firefox and IE, the Google maps seems to load extremely slowly.

You can find a post with videos at http://energykiosks.be/2014/feestelijke-inwijding-100ste-zonnekiosk-togo/

The part that becomes invisible is a div with class "yet-single"

.yet-single,
.yet-sheet {
    position: fixed;
    top: 200px;
    width: 40%;
    right: 7%;
    min-width: 210px;
    height: auto;
    }

.yet-single {
    padding: 39px;
    background: url(/wp-content/themes/yet13bisz/images/bg-pattern.png)repeat scroll 0% 0%;
    bottom: 20px;
    overflow: auto;
    overflow-x: hidden;
    color: #333;
    }

The Google map is an old map, https://www.google.be/maps/ms?msid=215783279080955007628.0004adcedefc7d3811050&msa=0, of which I imported the data in the Google maps engine, using the KLM, to add a new map background.

Any and all suggestions to resolve this, or to work around it, would be very welcome. TY!

update: I started an issue about this on Chromium issues: https://code.google.com/p/chromium/issues/detail?id=376252