selections in multi value pull down lists

Hi all,

I have a fairly lengthy pull down list in a section however for multiple selection, as in many cases it requires using the ctrl key to ensure previous selections are retained. Feedback is that people are finding this awkward and frustrated if they inadvertantly forget the ctrl key and have to start again.  Is there a way to make multi selections in a pull down list without requiring the ctrl key to be used?

Thanks in advance.