Robot presses Numpad del key instead of normal Del key

The robot is pressing the Numpad 'del' key instead of the NON-Numpad delete key.

Steps to reproduce
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1) Compile the attached code.
2) Trun ON the Numlock.
3) Run the attached code.
4) See the robot selects some text and then robot presses SHIFT+DEL
5) The text is cut.
6) Now close the application. And Trun off the Numlock.
7) Run the test again and see that text is not cut.
I have run this test on Windows 2k and solaris 9 same result.
This behavior is only seen if the key combination is Shift+Del. And it is not seen if I press only Del.
Run the attached application (RobotSwing) twice with NumLock turned off and turned on. Correct behavior is after one second it selects the text and presses "t" letter, so the whole text is replaced with letter "t". When NumLock is turned on, selection doesn't occur and t is typed after the existing text.