Disabling Work Offline in Firefox

I have been facing this issue in my firefox that when I start it, "Work Offline" box is checked by default and I have to manually uncheck to start browsing internet. And, here is the solution to turn it off permanently.

1. type about:config in address field of browser
This gives a warning saying you are changing advanced settings. Once you press the button that "I'll be careful, I promise!"

2. type "networkmanager" in filter tab and toggle the parameter(toolkit.networkmanager.disable) that you get when you type the above value in filter tab.

Reference is:
http://ubuntuforums.org/showthread.php?t=851542

The reason given in above link is- The network manager is not well informed , especially in dial-up situations and so, lets the firefox assuming that no connection exists and there by forcing "Work Offline". However, in my case, I had some network issues while booting up and so a manual restart of network was needed. However, even after fixing that issue, I was facing the above problem and there is no other option for me other than disabling network manager.