Odd keypad behavior with keyboard input

[daniel-widrick]

When running on windows 10 and using the numpad to enter numbers very quickly, the emulator misses some.

Steps to reproduce:

1. hold down 1 on numpad

• 1 appears on screen

2. hold down 2 on numpad
3. hold down 3 on numpad
4. release 1 on numpad
5. release 2 on numpad

• 3 appears on screen

end result: 13 expected result: 123