Ubuntu – Keyboard shortcut to switch focus between separate X screens

This was my problem too. Alt+<key above tab> didn't work to switch windows in the current application.

In addition, when i pressed and held down the super key to see the unity shortcuts, normally one would see this:

I'm assuming that is for a US keyboard? I stole the screenshot from another post, and on my danish keyboard it now shows Alt + Onehalf.

But when I had this problem, I did not see the line pointed to by the red arrow!!!

So check if you see a keyboard shortcut for "Switch windows of current application". If you don't this is for you:

The fix was as hinted at above to change the XKBMODEL setting in /etc/default/keyboard where I changed from XKBMODEL="microsoft4000" to XKBMODEL="pc105".

I did that and ran sudo dpkg-reconfigure keyboard-configuration. Not sure this last step was required.

Then I needed to reboot.

Now it works.

I've figured out what was wrong after trying a few things. I had to plug both monitors into the same kind of port, on the same graphics card. I had a hard time digging up the cables at home but once I got my hands on a pair of HDMI cables, I was able to set up the monitors correctly without much trouble.

It seems obvious now in retrospect but this didn't occur to me, especially since my Windows install on the same machine seemed to handle the original setup (two types of ports, two different devices) well enough. This makes perfect sense though.