I'm sure it is a simple change. The hard part is to find out where exactly should you do that simple change and how exactly should you do it. If you do not have experience with related APIs, you will need a day for googling and reading. Eclipse framework is huge and not all its parts are immediately understandable.

If you're experienced making Eclipse plugins, it would probably be under an hour. If you're not, it could take you a day to learn how.