Working with very long drop-downs can be a handful, especially since you can't set the size of the drop-down menu that opens. A much easier approach is to use a "live" filter, similar to the Google Auto-Suggest feature, where you start to type the text that you want to look for, and a menu pops-up appears with the relevant options. Up until now this was not possible to do in a PDF, but now it is!

Using this new script you can easily and quickly set up a plain text field to act as the "filter" for a combo- or a list-box field.

For example, let's say you have a list of all 50 states, and you want the user to be able to find their state quickly and easily:

You run the script and select your fields, and the additional options like whether the filter should be case-sensitive (set to false in this case), and whether to show all items if the filter is blank (set to true below):

After doing so, when you enter a letter into the filter text field, the options in the list immediately change to just those starting with the entered text:

As you type more letters, the options reduce even further:

If you wish to see this in action for yourself, the file shown above can be downloaded from here, for free.