Page overlay does not work (no replies)

Hello,

I'm using Piwik 1.12. I don't succeed to make working the "Page Overlays", on all the sites monitored here.

When I go on the "Page Overlay" of one of my application page, I see on the left the details of the metrics (Number of pageviews, visists, rates, etc.), and on the right, the corresponding page of the application. However, there is nothing more, no bubble or anything.

In the troubleshooting page, I've checked all the points and it still does not work.

I've tested with Firefox 23, Chrome 27 and IE8. There is no JavaScript error detected in the console.

Is there anything that I can do, or test to advance on this topic?

Thanks in advance.

Romain