fix

mix.exs

@@ -4,7 +4,7 @@ defmodule NITRO.Mixfile do
   def project do
     [
       app: :nitro,
-      version: "6.10.2",
+      version: "6.10.3",
       description: "NITRO Nitrogen Web Framework",
       package: package(),
       deps: deps()

src/elements/combo/element_comboLookupEdit.erl

@@ -22,7 +22,7 @@ render_element(#comboLookupEdit{id=Id, input=Input, disabled=Disabled, validatio
               case Multiple of
                 true ->
                   #link{
-                    class = [add-btn],
+                    class = ['add-btn'],
                     onclick = nitro:jse("addSortableItemFrom('#" ++ ListId ++ "', '" ++ InputId ++ "')"),
                     body = <<"+">>};
                 false -> []