Unworthy patron has Demeaning Inquiry. No Shift!?

BlitzMax Forums/BlitzMax Programming/Unworthy patron has Demeaning Inquiry. No Shift!?

Can someone tell me why MODIFIER_SHIFT does not work? I feel like an idiot asking because I know it's going to be something stupidly simple.

AppTitle = "Shiftless Window ver 0.8 Beta 2 (2006)"
Graphics 512, 32, 0, 60
Repeat
	If KeyDown(modifier_shift) Then SetColor Rand(255),100,100
	If KeyDown(key_a) Then SetColor 100,Rand(255),100
	DrawRect 0,0,512,32
	SetColor 180, 50, 230
	DrawText "Key 'a' works. But what's up with SHIFT!?", 80,10
	SetColor 0, 0, 0
	Flip;Cls
Until KeyHit(key_escape) Or AppTerminate()