I had the breadcrumbs feature activated on my old computer, and now that I've moved, I cannot enable breadcrumbs in Eclipse. I added the "Toggle Java Editor Breadcrumbs" button to the navigation bar, and the button is simply disabled. Same is true for the "Toggle Mark Occurances" button ...

Anyone know how I can reactivate this?

(Eclipse Version 3.4.1, Build id: M20080911-1700)