Unfortunately this issue is a bug within Chrome, and will need to be fixed by the Chromium team. (If you would like to view the issue and star it for updates, you can do so on Ticket 469194.)
To temporarily resolve the issue, reload the page. You will be able to tap one of these buttons (which sends an External Protocol Request to your computer) after doing so.
You can also use an external mouse, which will work every time.
This article was last reviewed by our Support team on July 9, 2015.