DBTree properties are not displayed correctly in edit mode regarding its parameters

# Create a class with a DBTree, with data in it (you can use 'usecase.xar' from XWIKI-11382).

1. Apply the patch proposed by Anca in XWIKI-11382.
2. Do not set "Use suggest" in the class
   
3. Select the "checkbox" displayer: on a sheet with the edit mode, a select field is displayed instead of checkboxes
4. Select the "radio" displayer: on a sheet with the edit mode, a select field is displayed instead of radio buttons
   
5. Set "use suggest" in the class
6. Now a displayer is used (from treeview.vm)
   
   This is really buggy.