12b36d5d_ebug_Preferences___FirebugWiki__Option
[Description] Specifies whether the Firebug window shall always be shown above all other windows [Valid Values] true, false [Default] false [UI Equivalents] Firebug Menu->Options->Detached Firebug on Top [Option] 
detachedFirebugOnTop
Firebug Preferences - FirebugWiki