Different behaviour in 12.04 and 14.04 when laptop lid closed with external monitor

Question

I upgraded from 12.04 to 14.04, and notice a different behaviour in multi-monitor mode. In 12.04, when I plugged in the external monitor and then closed the laptop lid, the laptop would not suspend and I could work with the external monitor, but when I removed the external monitor, I could suspend by closing the lid. In 14.04, when I close the lid the laptop suspends. I want to get back to the original behaviour: i.e.: close lid when monitor present = do nothing; close lid with no monitor = suspend.

This question How can I tell Ubuntu to do nothing when I close my laptop lid? gives solutions to always prevent the laptop from suspending, my question is specifically about different behaviours depending on whether a monitor is attached.

My laptop is a Thinkpad Edge 13 with Intel integrated graphics

(I found a similar question but referring to Ubuntu 11.04 Problems with external monitors on my laptop , the answer mentions a problem with the kernel)

Answer 1

I believe this is a bug, and the only solution is to set your options to "Do Nothing".

Quite simple really

go to System Settings Then click on Power Settings

Set the When the Lid is Closed options to Do Nothing

You can now close your lid and your laptop will not shutdown.

If your external monitor goes black just move your mouse or click mouse button and it should turn back on, and your external monitor will now be your primary display.

PS. You should also file a bug report for this issue.