Shift + Tab does works incorrect on an item that contains a sublist

Type

1. one
11. two
111. three

in the wiki editor, save and edit in wysiwyg.

In Firefox (tested on FF3):
Shift + tab to unindent on the "two" element will not work. Unindent button cannot be used because it's not active, due to problems in parsing valid lists.

In Internet Explorer:
Shift + tab unindents the element, but creates a new paragraph inside the list item.