// Define a policy name for window.close permission
// (assumes you don't have this pref already)
user_pref("capability.policy.policynames", "nowindowclose");
// Define policy: disable sites from using window.close 
// in their scripts
user_pref("capability.policy.nowindowclose.Window.close", "noAccess");
// List of sites subject to this policy
user_pref("capability.policy.nowindowclose.sites", "firstbadsite.com secondbadsite.com");

Many sites which offer specific "print formatted" pages do that: they assume that once you have finished with the print dialog you no longer want the page itself. So for your convenience they close it. Not so convenient for you, since you still want to view the page. I'm not aware of an easy solution for this. I can think of a couple different approaches. First, maybe there's an add-on to solve this? That would be easiest. Second, maybe there's a userscript to solve this? The Greasemonkey add-on runs userscripts which you can copy or download. Be careful to install only long-establish and trusted scripts. (''Is there a site that has this bad behavior that I can view without logging in? I will test one of my existing scripts to see whether it helps.'') Third, Firefox has an old system for restricting site permissions in a custom text file in your profile folder (named user.js). Editing this file is a bit advanced, and I haven't been able to test it, but the system works along these lines: <br>// Define a policy name for window.close permission // (assumes you don't have this pref already) user_pref("capability.policy.policynames", "nowindowclose"); // Define policy: disable sites from using window.close // in their scripts user_pref("capability.policy.nowindowclose.Window.close", "noAccess"); // List of sites subject to this policy user_pref("capability.policy.nowindowclose.sites", "firstbadsite.com secondbadsite.com"); Again, I haven't tested that and recommend looking into add-ons first.