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 ...
Just after posting this I checked the news and found that as of Monday night (July 13, 2015), Mozilla disabled Flash by default in its Firefox browser-- not just "old" versions of Flash as before, but all versions-- due to egregious bugs in Flash that were being actively exploited. This means I can't in good conscience use the flash plugin (in any browser) and hope that Collaborator at least limps along without it.