JqTransform Plugin Select Fields Not Working?

I am a big fan of the jqtransform plugin [URL]...e/jqtransform/ but have discovered that when you add to many select fields on a page, the bottom half of the select fields do not open the option fields.

I have a form which takes an passenger's date of birth, but there can be up to 9 passengers on a booking, so for every passenger there would be 3 select fields for the date of birth, the day, the month and the year. When I do not use the jqtransform plugin to style the select fields it works perfectly, but when the plugin is active the 3rd or 4th passenger's select fields's click event does not work anymore.

The code for this plugin can be found at the above mentioned url. Even you add more select fields on there example the bottom select fields do not work.