NotePanel layouts cannot use panels that have
been torn off. If you select a panel layout that includes a torn-off
panel, Maya displays a warning that it cannot use the panel. Any
available panel is used instead. For example, the built-in
Persp/Outliner panel
layout usually places the
Outliner in
the left pane and the
Perspective view
in the right pane. If you tear the
Outliner off
into its own window, a warning is issued and another panel is put
in place of the
Outliner.
Once you close the tear-off panel, it can be
used by panel layouts that include it.