Whisker is a different sort of object-oriented code browser for the Squeak Smalltalk environment.
The goal of the Whisker Browser (a.k.a. Stacking Browser) is to provide a simple and intuitive way to view the contents of multiple classes and multiple methods simultaneously, while using screen real estate efficiently and not requiring a lot of window moving/resizing. It does this by introducing the concept of subpane stacking. The principles behind Whisker could potentially be used by browsers for other object-oriented languages (Java, Python, etc.).
To open the Whisker Browser, use the 'open...'/'Whisker Browser' menu item in the World menu.