A Filter Select contains two components: a Text Box and a Select Box. The Select Box contains all options the user can select. Use the scroll bar on the right to browse through the options. If a Select Box is a multiple Select Box, you can select more than one option.
Searching for an option can be done using the Text Box on top of the Select Box. If you start typing, the Filter Select will automatically remove all options that do not fit to the keyword, meaning that an infix search is done on the options and not-matching options are removed.