Other CAPTCHA implementations installed with Extension Manager are not visible

1. Try to install the reCAPTCHA extension
2. Go to Administration to try and enable it
3. You will not find it in the list of available implementations (i.e. only JCaptcha shows up)

Workaround: Copy the recaptcha jar file (from the permDir/extensions/repository folder) to the WEB-INF/lib folder and restart the wiki. It should now be visible in Administration.