Btw, here is an older thread that discusses nearly the same:

If I find a way to have both I'll add it. It would probably be too technical and confusing to users who do not know the internals if I added it as an option.

That's an interesting alternative. The "save to camera roll" function is a good reason to do it that way - although I'd have to find a shorter button title...

Did you try the cursor navigation wheel by the way? 

I once implemented this and tried it out. Unfortunately, it interfered with vertical scrolling (if you disable auto line wrap) and zooming (two- and three-finger swipes were wrongly detected as pinch-to-zoom). So I didn't add this feature to a released version as a consequence.

Thanks for pointing that out. (The refresh button works too)

I have to admit that I haven't thought of this. I'll see if I can add it in an update.

Did you try to add the user name and password to the url? Like this: http://user:password@example.com/

I don't think it's possible to disable it after it's loaded. You'd have to reload the page or close it in the top right corner. You can either re-open the preview window or re-enter the url to reload the page without loading Firebug.