Hi kieriosity and welcome to the forums! You have come to the right place for InfoPath questions!
Wow, I think you have found a bug. Maybe the spelling parser is just taking a really long time to get down to the part of the XSL that is below the drop-down list, since it is so long. If you can reply with a consitent repro situation, we will forward to Microsoft so that they can fix it in the next release.
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge