There is an issue with what seems to be all versions of DT Register. I've verified it on an old 2.6.2 version and on the latest 2.7.11b version.
The issue is with the wysiwyg editor and DT Register. For some reason the editor does not load properly in DT Register when using the latest version of Firefox and Chrome. You are unable to edit any text in any of the areas where there is the wysiwyg editor. I've noticed the problem in the configuration and in the event properties. I've verified the issue with both JCE and TinyMCE. If you turn the content editor off though it works fine.
After rolling back to Firefox 8 everything works fine.
Guys... this was not a problem based on a particular browser or even DT Register... it was due to loading the editor inside of the Joomla tabs script. This has been an occasional issue on select sites, and of course seen more frequent in select browsers.
We've now corrected the issue by dropping the use of the Joomla tabs script in the configuration and event management areas and replaced it with another script. Now, the issue is gone. Get version 2.7.12c and you'll be set with this.