Thank you for your feedback. We were aware of both the issues you mentioned and here is what is changed for the Q3 release (due this week):
2. Improved - dragging of tiles is restricted to the confines of the TileView control. This is needed because the individual tiles, unlike a window, are not placed in a Popup element and if you try to drag them around your application they will remain beneath any visual element that is decalred after the TileView in your XAML code. Consequently, when the mouse pointer moves outside the TileView during dragging, the dragged tile remains within the TileView. This is the point at which it may seem the dragging is broken, since the user is still dragging but the tile is not moving. However, the tile will be moved even if the mouse pointer is outside the TileView, as long as it's not being restricted by the borders of its parent. A similar discrepancy is possible even if the mouse pointer is not leaving the TileView - while dragging, if the Tile reaches one of the borders of the TileView, the mouse will continue moving, but the Tile - not. What you will end up with is that the mouse will no longer be over the original position at which you started dragging the Tile. A side effect of this is that in the above-mentioned situation the tiles will swap positions not when the dragged Tile moves over them, but when the mouse pointer does.
I hope I was able to make things a bit clearer. Please let me know if you have any other questions.
the Telerik team