Question

I am working on an extension to FF. I would like to replace whole main window with my own layout. I know how to add and overlay over an existing main window

overlay chrome://browser/content/browser.xul chrome://foo/content/foo.xul

but how to add a layout that would substitute the main window?

This didn’t work (I still had the main window):

overlay chrome://foo/content/foo.xul

Where foo.xul starts with

<?xml version="1.0"?>                                                        
<overlay id="foo-main-overlay"                                               
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

    <script type="application/x-javascript"                                  
            src="chrome://foo/content/foo.js" />                             

    <toolbox id="navigator-toolbox">                                         

    ...                                                                      

Answer 1

You can use the override directive:

override chrome://browser/content/browser.xul chrome://foo/content/foo.xul

This will make sure that chrome://browser/content/browser.xul is replaced by chrome://foo/content/foo.xul. However, I hope that you don’t really want to replace the entire browser window…