yes, CSS Builder will always create a new design page.
If you save the design as a preset, you can delete the preset from the preset manager.
go to Insert -> Webassist -> Preset Manager to open the preset manager
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.