MACROMEDIA FLASH 8-LEARNING ACTIONSCRIPT 2.0 IN FLASH Manual page 721

Press Control+Shift+B (Windows) or Command+Shift+B (Macintosh).
In some previous versions of Flash, clicking in the left margin of the Script pane
selected the line of code; now it adds or removes a breakpoint. To select a line of
code, use Control-click (Windows) or Command-click (Macintosh).
To set and remove breakpoints in the Debugger, do one of the following:
Click in the left margin. A red dot indicates a breakpoint.
Click the Toggle Breakpoint or Remove All Breakpoints button above the code view.
Right-click (Windows) or Control-click (Macintosh) to display the context menu, and
select Set Breakpoint, Remove Breakpoint, or Remove All Breakpoints in the File.
Press Control+Shift+B (Windows) or Command+Shift+B (Macintosh).
After Flash Player stops at a breakpoint, you can step into, over, or out of that line of code.
(See "About working through lines of code" on page
You can set breakpoints in the Script window, and have them show up in the debugger if the
debugger has the same path to the ActionScript file as the one that was opened in the Script
window. Likewise, you can set breakpoints in the debugger during a debug session, and have
the breakpoints appear in the ActionScript file if you open it in the Script window.
Do not set breakpoints on comments or empty lines; if breakpoints are set on comments
or empty lines, the breakpoints are ignored.
About the breakpoints XML file
When you work with breakpoints in an external script file in the Script window, the
AsBreakpoints.xml file lets you store breakpoint information. The AsBreakpoints.xml file is
written to the Local Settings directory, in the following locations:
Windows:
Hard Disk\Documents and Settings\User\Local Settings\Application Data\Macromedia\Flash
8\language\Configuration\Debugger\
Macintosh:
Macintosh HD/Users/User/Library/Application Support/Macromedia Flash 8/Configuration/
Debugger/
722.)
Debugging your scripts 721