DescentBB

I have this problem with every keyboard I've used:
but when I tri-chord with any combination of keys on the keypad which uses \"enter\", any key that is not on the keypad is ignored, except for the down and right arrow.

Is this due to the construction of the keyboard, or is there anyway I could fix this with different drivers or something?

It's a keyboard limitation; I used to have the same problem.

Some people buy a different keyboard (check with Bubbalou, I think he has some recommendations for keyboards that don't have that problem).

Personally, I started using one of these, which works perfectly.

Very likely the keyboard construction.

Google/amazon for Keytronic keyboards. Get one that suits your style.

It's called key jamming.

I remember I had this same problem when I played D3.