Picker Field Not Recognized by Selemium Automation Script

I have an automation script that fills in the top half of a form correctly; these are text fields.  However, when the script comes to the first picker field it begins to type in the value but not suggestion list is returned from which the correct value can be selected.  It is like it does not recognize that a keypress is occurring.  Could it be that or does anyone have any other experience with using Selenium and Appian picker fields.  

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