EDIT: my "solution" below is not correct. It does the opposite:
0 = taskbar button flashes until you
click it
This sample chapter from the book "Microsoft® Windows® XP Registry Guide" contains some information related to focus:
The settings in the Focus category prevent that scenario by causing applications to flash
their taskbar buttons to get your
attention rather than stealing focus
from the application in the
foreground.
The default value for
ForegroundLockTimeout is 0x00030D40,
or 200000. This value is the time in
milliseconds before Windows XP allows
an application to steal the focus from
the foreground application. To convert
200000 to seconds, divide it by 1000
(200 seconds). You see the value
ForegroundFlashCount in the table
twice, because setting it to 0 causes
the taskbar button to flash until you
click it; otherwise, the taskbar
button flashes the number of times you
set in ForegroundFlashCount.
HKCU\Control Panel\Desktop
- Prevent applications from stealing focus:
ForegroundLockTimeout
- Flash taskbar button until I click on it:
ForegroundFlashCount
- Flash taskbar button N times:
ForegroundFlashCount
There is a registry setting in:
HKCU\Control Panel\Desktop
ForegroundFlashCount (DWORD)
Try to set it to 0.
Warning: be careful when you edit the Windows Registry.