Fix bug in dropdown

The menu for a multi-dropdown should only show entries that are not
already selected (there is no use case to select the same item more
than once).

modules/webapp/src/main/elm/Comp/Dropdown.elm

@@ -12,6 +12,9 @@ module Comp.Dropdown exposing
     , view
     )
 
+{-| This needs to be rewritten from scratch!
+-}
+
 import Data.UiSettings exposing (UiSettings)
 import Html exposing (..)
 import Html.Attributes exposing (..)
@@ -41,7 +44,8 @@ makeItem model val =
     { value = val
     , option = model.makeOption val
     , visible = True
-    , selected = False
+    , selected =
+        List.any (\i -> i.value == val) model.selected
     , active = False
     }
 

modules/webapp/src/main/elm/Comp/ItemDetail.elm

@@ -276,6 +276,7 @@ saveTags flags model =
     let
         tags =
             Comp.Dropdown.getSelected model.tagModel
+                |> Util.List.distinct
                 |> List.map (\t -> IdName t.id t.name)
                 |> ReferenceList
     in