Don't worry about red signal. Think whether how error message shows to you. Does it showing Expression Ok or it shows any error. If it is showing any error there must be problem. The case, may be share image for expression. If it is showing Expression is OK Syntax is right but Qlikview just consider as there agenda nothing new. It will work as you expect when expression seems ok.
Life is so rich, and we need to respect to the life !!!