Go to http://build.fluidproject.org/infusion/demos/reorderer/imageReorderer/html/imageReorderer.html
Select image and try to use Ctrl + Arrow key combinations. You will see that OS has a priority for those key combinations and therefore the component cannot be controlled through those key shortcuts.
Firefox 29.0.1 & Chrome 35.0.1916.114
Instructions need to be specified for Mac OS to use the Command+Control+Arrow keys to move the avatars.