"windows > settings/prefs > interface >" will give you a good idea but its not real clear.


Its the same for 5 as it is for 4.5. Window > Settings/Preferences > Preferences . From there make sure the "Interface" is highlighted under the categories list. Down that list to the side, you will see Open Attribute Editer, have the In Separate Window checked on.

The open tool settings in a separate window is also kinda cool.