Found what seems to be the best solution on a forum:
The ultimate solution (for Ubuntu anyway) is to use CompizConfig Settings Manager, click through to the “Windows Management” subsection and then click into “Move Window”. In the “Initiate Window Move” option, change the button value from Button1 to (for example) Button1. Hey presto, you can now move windows by holding down the Windows key and Button1 on your mouse, and Alt for loop select will work just dandy!
