Instead of storing the entire line in the drop box (which I doubt anyone can read anyway), you could display a shorter version, or synopsis of the text you are trying to pass in the drop box and use this as a reference when you are exporting. For example:
DropBox Options:
-Brown dogs run fast.
-Cats eat mice.
-Mice like cheese.
Then, whenever you are running your export code you will know that when "Brown dogs run fast" is chosen in the drop box you must export "The brown dogs across the street where I live in New Hampshire are probably the fastest dogs on the face of the planet."
I hope this makes sense, let me know how it works. However, I am curious on why you would make a drop box with 256 character options; wouldn't that fill almost 3 pages horizontally and look horrible?
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Matt Faus
InfoPath Dev Texas
Matt Faus / Microsoft InfoPath MVPQdabra® Software / Streamline data gathering to turn process into knowledge