How to Fix "Mark Occurrences" in Eclipse?

Eclipse is a great editor, and among it’s many wonderful features one of my favorites is the Mark Occurrences feature. However, I recently installed the Aptana plug-in, and in trying to configure it I somehow managed to break Mark Occurrences in my Eclipse installation.

The feature still works somewhat, but instead of highlighting all occurrences of a given object, it now only highlights the occurrence where it is first created. In other words, in:

1. Dog dog = new Dog();
2. dog.bark();
3. dog.bark();

Only the “dog” in line 1 would be highlighted, not the “dog” in 2 or 3.

However, before I know I had things configured such that all three “dog” references would be highlighted by Eclipse. Does anyone know what configuration option I changed to “break” the marking of occurrences like this?

How to Fix "Mark Occurrences" in Eclipse?