Since the upgrade to 15.04
(update: 15.10
still same), my laptop's behavior on closing lid has changed: if it is connected to an external monitor, it will not suspend. In addition, all the windows are now flushed to the external monitor. This seems like a deliberate feature and not a bug.
How do I configure the laptop to suspend even if it's connected to an external monitor?
This is Lenovo Thinkpad T440s on Ubuntu 15.04
/15.10
with Intel graphics.