Wrong behaviour when listbox panel is StackPanel FlowDirection="RightToLeft" Orientation="Horizontal"

[mesta1]

I have a listbox with ItemsPanelTemplate set to:
StackPanel FlowDirection="RightToLeft" Orientation="Horizontal"

There is a wrong behaviour when dragging from middle or righ-most item and dropping before the left-most item.
I have two different behaviour:

1. in one project i didn't implemented the interface IDropInfo and when i drop it, it drops after the left-most item and not before.
   example:
   [5] [4] [3] [2] : i grab [2] and put before [5]
   expected = [2] [5] [4] [3]
   result = [5] [2] [4] [3]
2. in another project i implemented a IDropInfo interface and it's working, but the preview is shown on the right and not on the left.

example:
[5] [4] [3] [2] : i grab [2] and put before [5]
expected preview (the character "|") = | [5] [4] [3] [2]
result = [5] | [4] [3] [2]