I have added a multiselect control in my dialog with i18n = true.

Part of the JCR dialog looks like this
==============
Dialog definitions (please press edit, I don't know how to make this text look good in this type of editor)

• tsTabContainer
  • tabMain
    • tabTitles
      • controlType = multiselect
      • description = "Enter the title texts for each tab headline"
      • i18n = true
      • label = "Tab titles"
      • required = true
      • saveMode = multiple
      • type = String
    • controlType = "tab"
    • label = "Tab"

This works:
<#list content.tabTitles_sv_SE?values as tab>
<#/list>

<#list content["tabTitles_" + state.locale]?values as tab>
</#list>

This does not work:
<#list content.tabTitles?values as tab>
</#list>