I'm using Firefox 2.x on Gentoo Linux 2008. I am going to be making a change here at work so that I no longer use a mail client, but use our web mail system. It may not be ideal compared to running Thunderbird, but I need to learn the web app enough to train users on more advanced features. The only way to do that is to live with the web app every day. My main annoyance with running most web apps (AJAX, Flash, what have you...) is that the browser always has the navigation toolbar, and the bookmarks toolbar at the top which makes any of these things feel less like an app and more like a web page. This is especially fruitless when you're not supposed to use the navigation bar to move around the app.

So what I'd like to do is launch Firefox pointed specifically at the web mail app's URL where it will open in a window with only the bottom status bar showing and nothing else. Ideally, even the menu should be gone. I've seen people do this with pop-up ads, and I imagine that's done on the web server side. But is there any other way to do it? I looked through the firefox command line options and nothing seems to touch on this. I suppose even a local HTML file that is opened by the browser would be good enough, but where do I even start with that? I imagine that would be fairly simple. Any suggestions as to where to start? I'm not a web developer, so be gentle with me.

A friend suggested one approach. Just save this into a file and call it something.html (in my case it's zimbra.html):

That brings up my web mail app in a popup window. But it also opens a new browser tab or window in my running browser first for the zimbra.html document. I also tried launching it from the command line like this:
That opened up the app in a popup first. Then it opened a new blank browser window for the zimbra.html file. So I'm close but not there yet...

You can use XULrunner to run completely customized "skins" with no navigation bars etc.