           switch tagKey
             when "art_file:bitmaps", "art_bitmap:bitmap_id"
             else
-              object.userProperties[k] = v.toString()
+              userProperties[lowerCamelCase k] = v.toString()
               @log "WARNING: unknown tag:attribute: #{tagKey} (ignored)"
+
+    object.userProperties = userProperties
 
     if children = tag.tags.children
       @populateChildrenFromTag object, children

        when "art_engine_version" then # ignored
        when "kimi_editor_version" then # ignored
        when "composite_mode" then @setCompositeMode object, v
        when "drop_in_enabled" then object.userProperties.drop_in_enabled = true
        when "lock_mode" then # ignored

        when "handle", "w_val", "h_val", "x_val", "y_val", "x_layout_mode", "y_layout_mode", "stack_mode" then # handled elsewhere


    @decodeLayout object, tag, parent

    userProperties = {}
    for k, v of tag.attributes
      switch k
        when "name" then object.name = v
