One of things I love in ides is the ability to double click to select a var and then it shows all the other instances of that var in scope. IDEA does this UNTIL I start scrolling past the original double-clicked var, at which point it then switches to the next defined var at the top of the screen.
For example, if you have..
int age = 0;
int score = 0;
and you double click on 'age' you'll see all 'age' instances in scope . Now say you initilally selected age while it was in the middle of your view, now start to scroll down the file - As soon as the initial 'age' rolls off the top of the file it switches to highlighting instances of "score" in scope. As I can continue to scroll down it will switch to new definitions as they are declared.