How to enable debugging or attach debugger in visual studio with silverlight when browser is firefox

Today I was facing problem in attaching visual studio debugger while using firefox. I kept googling here and there and then almost spending 3-4 hours, Some where i found that when you use IE then your debugger will get attached. I tried it and the problem was solved. Finally the debugger got attached with IE and not with firefox. Then further googling gave me following solution in which you have change the config of the firefox

Solution:

• In Firefox address bar type about:config
• Read the warning, choose your preference to always remind you or not and accept
• In the search bar of the config options now type: npctrl
• You should then see the entry: dom.ipc.plugins.enabled.npctrl.dll
• Change the value from true to false (simply double-clicking will change this for you)
• Restart Firefox