Never use a WYSIWYG editor for ANYTHING except for maybe blog posts. xD
Using a wysiwyg editor for coding websites is horrible practice, and can lead to bad code, browser dis-functionality, and bad taste in your peers mouths. I can understand wanting to see the output of your code, but that can be achieved simply by developing locally and saving when you need to see if something works.
Alternatively, you can use NetBeans IDE, which has support for PHP (as well as HTML and CSS). The CSS view even has a preview where you can see what your CSS might look like (Again, better than dreamweaver trying to tell you what you're going to see, and then being upset when you load it in an actual browser and seeing it's horribly deformed)
Me, this is what I use when I'm coding/designing:
NetBeans IDE, Programmer's Notepad, Photoshop, Calculator (not on the pc, in my hand), Google Chrome, Firefox (for firebug).
That's it. I always debug as I go, and even then I don't debug till it's all done, meaning I code all the HTML, and ALL the CSS, and then I debug from there. It's actually a great productivity tool. Because then, if something is not right or you can't complete something, it's easy to move on and fix the next thing, rather than having to go back and try to regain your train of thought.