opalexecutable you can write something like
$ opal -I../opal-browser/opal --gem paggio --compile your_code.rb
require 'opal-browser'before compiling the code to register all paths
A version selector on Try Opal would be amazingly helpful.
In this case I just know that making the second parameter true made something work in 0.11 that had worked in 0.10. I don't know which one the bug is in though, just because it worked before doesn't mean it was working as intended.