Here is a review of some research on managing the explosion of information in an IDE. Note that all of these are based on Eclipse, which appears to have become the dominant platform for IDE research.
Mylar is an experimental Eclipse plugin that tracks what program elements you are interested in, by watching your editing/browsing behavior. It alters the standard views such as the Package Explorer, Outline, and Type Hierarchy to focus in on what you have expressed interest in. Uninteresting things are filtered out, and the interest-level of the remaining things is indicated by different shades of highlighting. You can manually establish “landmarks” on program elements, which drive certain views to automatically display related elements, such as a type hierarchy filtered down to show only the inheritance structure of the landmarks.
Relo takes a different approach: instead of filtering the system down, it lets you build up a diagrammatic view of just the parts you are interested in as your explore.
JQuery lets you build a custom broswer by writting queries over your program. The results are shown in tree form, and you can expand any leaf with another sub-query, either custom or standard.