I also have issues with the Safari version 7.12.7 of Web Clipper -- it disables the arrow keys on both of my keyboards for use in Lumosity after 2-3 arrow key presses. Lumosity has highlighted that it is an issue as follows with Chrome web Clipper -- but I also have it in Safari.
"What should I do if the games do not respond to the arrow keys or keyboard?
If the games are not responding to your keyboard, there are several troubleshooting steps you can try.
Do you have an extension called Evernote Web Clipper installed on Chrome? Recently this extension has been preventing games