Seems that a loop is not in place or something else. Can you give me the language you are using and a snippet of your code? This will help me answer you.
If you are trying to externally draw a crosshair over CA, this fails to happen. I first posted a autoit script with an executable to do this back in September (probably the first person to do something of the sort). I even included the source.. You can see where this is going can't you? The method got patched after a few weeks when someone else (a fellow member) posted it with Visual Basic. It turns out that it gave a very small black crosshair instead of the one you try to lay over top. It now may not even show anymore.
If you are trying to do this in a DLL form, refer to the first sentences. Thanks!