Array order not being retained by x-editable inline dropdown/checkbox list.  #5083

Bug Description

Under some circumstances, the order of elements in the x-editable popup inline editor may be different to those in the main dropdown element of the same field on the Edit page.

How to Reproduce

• Inspect the 'data-source' value of the inline value of userclasses for a user in Admin -> Users.
• Take note of the order of values.
• Click the inline editing link and review the order of values.
• The order may be different, depending on the number of userclasses and values.

Expected Behavior

The order displayed in the popup inline editor should match the order within data-source.