how to show listbox items show clearly use "readonly"

Excuse me!  I do work-flow, I have a question,about this: a staff apply a form to manager,when staff apply,there is a listbox which have 5 items, staff can choose one or two or more,if manager receive this form ,he can't to change this listbox items which staff have chosed. My manager told me use listbox items "readonly",but it can edit too;if use "enable=false", it can  not edit,but the forecolor dosen't show clearly which i have chosed. Manager told me can't use other color,use default. how can i do? help me!