Firebug & Split Browser - Firefox extensions

For those who have a problem of using Firebug after installing an extension, Split Browser, my suggestion is to uninstall the extension. This may not be an exact solution but it works for me.

A week ago, I could not open my Firebug...I tried to enable all functions but it didn't work at all. I assumed that it might be a newly added-on extension, Split Browser, which may be a conflict of opening Firebug. So, I decided to uninstall it and now, the Firebug works.