The ProcessBrowser lets you see and interact with the various Processes
(threads) inside Squeak. It brings up a three pane window containing a list
of processes, sorted by priority. When a process is selected from this list,
a stack trace is displayed to the right of the process list. And when a 
particular stack frame is selected from the stack trace, the source code of
that method is displayed, with the current location of program execution
highlighted in red.

A context menu in the process list lets you inspect, explore, profile, or 
locate objects pointing to the selected process. You can also interrupt
the selected process and debug it, and then resume the process from
the debugger. And the context menu in the stack pane lets you inspect
the receiver of a selected message or other values in that stack frame.