Traca, this one certainly does. But that doesn't imply all do.
Here's what's in another non-dairy icing (Rich’s® Bettercreme® Icing and Filling)
High fructose corn syrup, water, partially hydrogenated palm kernel oil, partially hydrogenated soybean oil, contains less than 2% of the following: Sodium Caseinate (a milk derivative), soy protein concentrate, polysorbate 60, carbohydrate gum, sugar, salt, artificial flavor, soy lecithin, polyglycerol esters of fatty acids, to preserve freshness (potassium sorbate), xanthan gum.
See. No flour.
(I never cease to be amazed at the alchemy involved in converted liquids to solids.)