Custom List Enhancement

This is a possible enhancement request. 

Allow users to select multiple items from a Custom List (e.g. Test Case > Custom Properties > select multiple items from a list by allowing the use of CTRL / Shift + left mouse button to select multiple values from the list.)

What I am trying to do is to show functional coverage of test cases for various components of a system. 

I could use the free text field, but this would allow people to add 'their own interpretation' of the functionality that is being tested, thereby making reporting / filtering almost next to useless.

I hope this makes sense.

Cheers

J