Dreamweaver is not a web browser, sometimes it will not render things correctly in design view, but the browser will render fine, if it renders correctly ion the browser, you can ignore the issue in Dreamweaver.
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.