The problem you'll run into, with anchor tags and importing your campaign from a pre-designed URL, is that we insert a <base> tag into imported html. Normally, that's great, since it means you can code the html just like you would usually - with relative urls, images srcs, etc. But that, however, kills the ability for anchor tags to work.
If you know that you'll have full urls in your content, add a blank base tag and we won't override it. Something like this: <base href="">
Further Explanation
The way a browser interprets a <base href="xxx"> tag is that the "xxx" part is prepended to every <a href="blah"> , <img src="blah">, etc tag. Unfortunately that also includes anchor tags. So, with something like this:
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <base href="http://www.yourdomain.com/"> </head> <body> <a href="#section1">test anchor link</a> <a name="section1">test anchor</a> </body> </html>
In the popup preview, "test anchor link" will actually point to "http://www.yourdomain.com/#section1". You will see that behavior in a regular campaign as well (without importing from a url).
We automatically add the <base> tag in any campaign imported from a URL if one doesn't exist. Since, most of the time, that's going to have the best results (most people use relative urls for images, links, etc).
Since we only add the base tag if one doesn't exist, when you set href="", the browser essentially prepends nothing. Which will allow anchors to work.