Inspired by James McKay:
So, when you want to email someone from CaseWorks, you can easily have the email populated into your email screen. When you hit the search button, and select someone to email to, that person's email will be populated into the TO or CC or BCC fields ( depends on which button you select 
Then you will be presented with the following:
Where you can filter for the person or add a new person as required.
You might have to clear your browser cache
