I was mucking about with David Bailey's ID and library resize issue and I got the attached.
3libraries.JPG 106.83KB 0 downloads
I'll try to work out exact steps but the basics are.
Open a new ws.
Open ID in horiz. mode
Open the library - I have it on by default in new ws
Flip the ID to vertical and try to resize the library larger and smaller.
Flip ID to horiz and again resize the library.
Do this a few times then do File -> New Workspace. This should flicker the display a little and then give you two libraries in the one w/s
Do it again (File -> New Workspace) and you should have three.