Open Groovy app.
Click on Groovy Console tab.

See spinning loading icon.
Note that trying to launch other apps via applauncher is not possible.

Possibly missing or misconfigured jquery.terminal.

Log shows:
Nov 13, 2013 2:52:13 PM com.vaadin.server.communication.PublishedFileHandler handleRequest
WARNING: jquery.terminal-0.7.7.min.js published by info.magnolia.module.groovy.terminal.Terminal not found. Verify that the file info/magnolia/module/groovy/terminal/jquery.terminal-0.7.7.min.js is available on the classpath.
Nov 13, 2013 2:52:13 PM com.vaadin.server.communication.PublishedFileHandler handleRequest
WARNING: jquery.terminal.css published by info.magnolia.module.groovy.terminal.Terminal not found. Verify that the file info/magnolia/module/groovy/terminal/jquery.terminal.css is available on the classpath.
Nov 13, 2013 2:52:13 PM com.vaadin.server.communication.PublishedFileHandler handleRequest
WARNING: terminal_connector.js published by info.magnolia.module.groovy.terminal.Terminal not found. Verify that the file info/magnolia/module/groovy/terminal/terminal_connector.js is available on the classpath.