LuaLua forced keeper Karl Darlow to make a scrambling save in only the third minute after being fed by Stephen Ward, and two minutes later he fired an angled shot over the bar from inside the area.
Darlow later dived to hold a bouncing 30 yard drive from Ashley Barnes before Forest came close to breaking the deadlock.
An accurate cross from Andy Reid found striker Henderson and his goal-bound header was pushed round the post by Polish goalkeeper Tomasz Kuszczak diving to this left.
Kuszczak was alert again mid-way through the first half when he beat away a firm drive from fellow countryman Radoslaw Majewski.
Lansbury and Reid both put shots wide for Forest before Wales international Crofts put Brighton ahead in the 31st minute from close in.
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