al_key_down ignores shift for num lock on + key pad press (Windows only)

[oitofelix]

On Windows, al_key_down doesn't detect ALLEGRO_KEY_{L,R}SHIFT press when Num lock is on and ALLEGRO_KEY_PAD_? is pressed simultaneously. This works fine on GNU/Linux, though.

[SiegeLord]

Windows sends us an extra KEY_UP event when you hit a numpad key while holding shift, as this log from ex_keyboard_events shows:

KEY_DOWN  code=215, char=' ' (   0), modifiers=00000000, [LSHIFT]
KEY_UP    code=215, char=' ' (   0), modifiers=00000000, [LSHIFT]
KEY_DOWN  code=043, char=' ' (   0), modifiers=00000000, [PAD 6]
KEY_CHAR  code=043, char=' ' (   0), modifiers=00000200, [PAD 6]
KEY_UP    code=043, char=' ' (   0), modifiers=00000000, [PAD 6]
KEY_DOWN  code=215, char=' ' (   0), modifiers=00000000, [LSHIFT]
KEY_UP    code=215, char=' ' (   0), modifiers=00000000, [LSHIFT]

That shows me pressing and holding shift, tapping numpad 6 (with numlock on as modifiers show) and then releasing shift. Despite that I get 2 down and up events for the shift key.

As far as I understand this is a limitation of the input API we're using (Win32). It's not obvious what can be done about this.