To display a drop-down list containing the Document Types available for full-text searches, set the value of the showDocTypes key to true. For example:
"showDocTypes": true
Users can use the list to select a specific Document Type to perform a full-text search for. To hide the Document Type drop-down list, set the value of showDocTypes to false.
Note:
If the Document Type drop-down list is hidden, you must specify a single Document Type to search on. See Specify a Document Type for more information.