Collaborator (and all Web-based tools, really) should retire any use of Adobe Flash. The same functionality is now available natively in standards-compliant HTML5 browsers, which are commonplace at ...
We're looking at either making its presence a configurable option or dropping it entirely soon. It's there primarily to support (older versions of) IE. I'm leaning towards dropping it on the theory that it causes more problems than it solves (the things it solves are at best inconveniences compared to the security vulnerabilities it opens users up to). As a stopgap, you can limit flash to only execute on your Collaborator host via things like adblockers that support whitelisting.