After you set a breakpoint, you can deactivate it, activate it, or
  cancel it.

  Deactivating a breakpoint causes the debugger to ignore it during
  program execution.  However, the debugger keeps the breakpoint listed
  in the breakpoint view so that you can activate it at a later time, for
  example, when you rerun the program.  Note the following points:

   -  To deactivate a specific breakpoint, clear the button for that
      breakpoint in the source view, the instruction code display, or in
      the breakpoint view.

      In the breakpoint view, you can also choose Toggle from the Break
      menu, if the breakpoint is currently activated.

   -  To deactivate all breakpoints, choose Deactivate All from the Break
      menu on the main, instruction, or optional view window.

  Activating a breakpoint causes it to take effect during program
  execution:

   -  To activate a breakpoint, click on the button for that breakpoint
      in the source view, instruction code display, or in the breakpoint
      view.

      In the breakpoint view, you can also choose Toggle from the Break
      menu, if the breakpoint is currently deactivated.

   -  To activate all breakpoints, choose Activate All from the Break
      menu on the main, instruction, or optional view window.

  Canceling a breakpoint causes all information about the breakpoint to
  be lost.  Once you cancel a breakpoint, you cannot later reactivate it,
  but must again explicitly set the breakpoint.  Note the following
  points:

   -  To cancel a specific breakpoint, choose Cancel from the Break menu
      on the optional view window.

   -  To cancel all breakpoints, choose Cancel All from the Break menu on
      the main, instruction, or optional view window.