error while processing [TRUE ===FALSE]

I have the following in debugSampler

isBooth=FALSE

I have if controller with condition:

${isBooth} ===FALSE

it producess exception:

2016/04/06 18:43:51 ERROR - jmeter.control.IfController: NL for hh: error while processing [TRUE ===FALSE]
 org.mozilla.javascript.EcmaError: ReferenceError: "TRUE" is not defined. (<cmd>#1)

How to fix this?