If you update the following two files to the latest versions found here:
you should have a double-click available. Use the "Original format" link at the bottom of the above web pages to get a downloadable version of the file, and remember to make a backup of the original file before overwriting it in case you need to restore the original.
To use the double-click, the comments read:
// Override this method in an external script to implement
// your own double-click handler.
// e.g. mapFrame.OnDblClick = MyOnDblClick
// where MyOnDblClick() is a function in your script
Tom Fukushima Software Development Manager ICP - IPG Autodesk, Inc.