7f5ad477_ebug_Preferences___FirebugWiki__UI_Equivalents
[Option] detachedFirebugOnTop [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
Firebug Preferences - FirebugWiki