Making Firefox maximize on startup

You’d think something like this would be incredibly easy, maybe even be in an options tab or possibly prefs.js in the user’s profile.

Eh, sort of.

The setting is in localstore.rdf within the user’s profile. This value is supposed to be saved automatically when closing out of the browser, as this page mentions.

In my case I want a lab of users to all receive the same “maximize window” setting. Thankfully, the user profile being used is thin and I don’t have to worry about them having a personalized localstore.rdf file.

Here is the file I’ll use:

<?xml version="1.0"?>
    Purpose: Set the Firefox window to maximized. This file would be copied
             over on every login, thereby preventing the window from coming up
             sized smaller. Users are able to size it themselves during their
             browsing session however.
<RDF:RDF xmlns:NC=""
  <RDF:Description RDF:about="chrome://browser/content/browser.xul#sidebar-title"
                   value="" />
  <RDF:Description RDF:about="chrome://browser/content/browser.xul#main-window"
                   sizemode="maximized" />
  <RDF:Description RDF:about="chrome://browser/content/browser.xul">
    <NC:persist RDF:resource="chrome://browser/content/browser.xul#main-window"/>
    <NC:persist RDF:resource="chrome://browser/content/browser.xul#sidebar-box"/>
    <NC:persist RDF:resource="chrome://browser/content/browser.xul#sidebar-title"/>

Here is the relevant value:


Hope somebody finds that useful. 🙂