Steps to reproduce:
1) Create a list view with selectMode="multi", and attach a drag source to it.
2) Select multiple items, then click to drag the selection out of the list view.
You expect the multiple items to be dragged
Upon mouse down, the selection is reset to be a single item, causing you to drag just one item.
If you hold down CTRL or SHIFT as you begin your drag, you can kind of work around this issue, but that is obviously a less-than-ideal user experience.
Note that this could affect TableView and TreeView as well, though they weren't tested as part of this ticket.