Steps to reproduce:
- Login as an admin
- Hover over "Wiki" and click on "Administer Wiki"
- Click on "Groups"
- Click on the small yellow pencil to the right of the group you want to edit (in my case XWikiAdminGroup)
- Start typing the group's name in the "Subgroups to add" input field
- If the group exists a suggestion will be displayed (subgroup.png)
- If the group doesn't exist the suggest shows: "core.widgets.groupPicker.noResults" (subgroup2.png)
If you try the same scenario for the "Users to Add" field you don't get that message (user.png).
Tested on Chrome 23, Firefox 17 and IE9.