Since the keyboard interface provides only one action for the ALT key, both ALT keys should work to perform the designated action.
-mikeyww
Actually, that's incorrect. They give different virtual keycodes, for the express means of using them differently.
The Virtual Key Code for Alt is VK_MENU, but is extended into VK_RMENU, and VK_LMENU.
Try CTRL+ALT+DEL using the keys on the right side of the keyboard. It doesn't work. So this is more a function of implementation, than error. And if the workaround works, it seems that it may be functioning as designed- that's mouser's call, though it will affect at least myself if he does change it.
The distinct Virtual KeyCodes from MSDN:
VK_MENU
0x12
ALT key
VK_LMENU
0xA4
Left MENU key
VK_RMENU
0xA5
Right MENU key
To Tom's excellent point, when you press right alt you get the following:
vkCode: 162, wparam: 260, lparam: 3398032
vkCode: 165, wparam: 260, lparam: 3398032
And when you release, you get the following:
vkCode: 162, wparam: 257, lparam: 3398032
vkCode: 165, wparam: 257, lparam: 3398032
It's sending two keys - the shortcut for CTRL+ALT.
AltGr+Del used to do the same as CTRL+ALT+DEL, but it's handled at a lower level than normal key combinations now.