I installed STS 2.2.1 and added Groovy and Grails support. It works well.
However, there is not short cut key for the Grails command prompt. I can navigate to the menu item under Navigate menu and open a command prompt. No short cut keys are shown to the right in the menu item and Ctrl + G does not work. I expect I could define my own short cut key mapping but this should work out of the box according the install instructions.
The PC run 64 bit Kubuntu with KDE 4.3.