Problem with checkbox macro // array (SC2)

Hey everybody,

I am having a hard time understanding how to use the <<checkbox>> macro in SC2:

<<set $rightAnswer to [true, false, false, true, false, false, false, true, false]>>

<h3>Which of these ingredients do you need for the potion?</h3>
<<checkbox "$userInput[0]" false true>>stinging nettle
<<checkbox "$userInput[1]" false true>>mandrake
<<checkbox "$userInput[2]" false true>>yellow cress
<<checkbox "$userInput[3]" false true>>fly agaric
<<checkbox "$userInput[4]" false true>>asarabacca
<<checkbox "$userInput[5]" false true>>woodruff
<<checkbox "$userInput[6]" false true>>garlic
<<checkbox "$userInput[7]" false true>>lady's mantle
<<checkbox "$userInput[8]" false true>>puffball

<<button Check>>
	<<if $userInput == $rightAnswer>>
		<<goto "correct">>
	<<else>>
		<<goto "false">>
	<</if>>
<</button>>

I try to compare the two arrays, but the condition in <<if>> is never met, as $userInput remains empty.
What am I doing wrong?