On-screen display of build number since a recent security update -- why?

[Thomas Adams]

I'm running a German SB version of Windows XP Professional. It was
installed, activated, upgraded to SP1 and then brought up-to-date via
WindowsUpdate regularly. Since one of the last security updates there's a
message in the lower right corner of the screen indicating the build number.
("Nur für Testzwecke. Build 2600.xpsp2.030422-1633 (Service Pack 1)").

This message shouldn't be there and I can't switch it off with Tweak UI. Can
anybody explain please why it is there and how I can make it go away?

In the registry, the following key is set to "0". According to an article I
found in TechNet, this should take care of making the message disappear. But
it fails.

HKCU\Control Panel\Desktop\PaintDesktopVersion

 

[Smile Extender]

You might have installed non-product version of hotfix. Try to uninstall it
and check if there is correct version available. If not, report that to
Microsoft. They shouldn't deliver test versions for normal users.