If you are using a Page Viewer to embed a youtube video (via url format: http://www.youtube.com/embed/sdflkjhC8), you may come across an issue where if you also have a picture gallery that pops open in a new window, the youtube video stays in the foreground of the picture gallery. Basically, a z-index issue.

The quickest fix is to simply ammend the youtube URL to include “?wmode=transparent”
So from the example URL above, you would change your page view webpart link to be this instead:

“http://www.youtube.com/embed/sdflkjhC8?wmode=transparent”

Works like a charm.

Original:
http://www.scorchsoft.com/news/youtube-z-index-embed-iframe-fix