On the left side of the main Peek-a-Boo window are the icons for each running process; each icon may have a radio button. The selected (filled) radio button shows which application is in front. Clicking a radio button brings that application to the front. This can be quite convenient for rapidly navigating running applications.
Some applications will not show a radio button. These applications (such as File Sharing Extension) are background-only applications, and can not be brought to the front.
The top of the window contains a map of the Macintosh's memory. This memory map shows how much of the Macintosh's memory is being used, and how it's being used. The dark gray portion is memory used by the system; the colored portions of the memory map show memory used by processes. If a process is selected, that process's memory is colored a bit darker. This can be convenient, since sometimes a large chunk of memory is "blocked" by a small application in the middle of it. Peek-a-Boo lets you find these situations and deal with them; if you quit the small application, you can then launch an application that needs the big chunk. In many cases, there's even memory to launch the small application again!
For your convenience, you may click on a process's memory in the memory map and it will be automatically selected.
If you click on a process, you select it. There are several ways to manipulate processes; see the Processes Menu section for more information.
If you start typing the name of a process, Peek-a-Boo will automatically select it. You can also use arrow buttons to navigate through the process list: the up and down arrows select up and down through the process list; the left and right arrows select based on the location in memory. (I.e. it goes left and right through the memory map.)
Many pieces of information in the main window may or may not be showing, depending on the Preference settings. For a further explanation of these items, see the Preferences section.
The "process header" is the part of the screen above the processes and below the memory map. Each heading has a double vertical bar that may be dragged to resize the width of each column. (Holding down "option" when click-dragging will do a "live" refresh while you're resizing.)
Some headers are bold. These are headers that you can click on to change the sort order of processes. You can sort processes based on the following fields:
There's a "sort direction" icon above the vertical scroll bar to specify whether it sorts from the smallest value to the largest, or from the largest to the smallest.