a Supprising Use of Win32 API KillTimer

You can kill any timer of other instances by using KillTimer() in your program as following:
1,Call FindWindow() to got HWND of the window you want to kill its timer.
2,If you don't know the id of timer, just change it from 0 to 255, or other number you want to search.
3, Call KillTimer(HWND, id), and you will be surprised that it succeeds.
Obviously it has not security and may cause problem in some case when timer is important.
I feel deceptive.It may be a bug of Microsoft



al