So I know how to create a webpage with dashcode (3.0.5). If I start a new project I can create a webpage/website by simply using the GUI, drag and drop items, resize WITHOUT coding. However, if I open an .html file with dashcode after I create a site the code opens. I cannot figure out how to edit the page as I can when I first create a page. I'd like to use the IDE that allows me to drag and drop things with ease, not manipulate the HTML.
When you're trying to open your project, make sure you're opening the .dcproj file since this is the actual Dashcode project, rather than the exported HTML project.
Opening the .html file created by Run & Share won't work in Dashcode's actual project editor, and will show the HTML code just as you mentioned. You have to open the Dashcode project file, saved as .dcproj by File → Save.
I don't know about Dashcode, but if you want to use an IDE for easy editing of HTML then go for Dreamweaver/Coda/Espresso IDEs. They provide nice built-in APIs to ease programming. Taco HTML is a tool where you can easily debug and manipulate your HTML code, but there is no drag and drop there.