Solved!
Thank you for your help! It was the css rule (overflow hidden). I did not change the javascript line in the head of my html-document.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.