When an object (image/frame etc) is dragged-n-dropped, some target locations are
not accepted by Writer. In such cases, the user is not provided with any clues
before he drops the object: He wil come to know only when he drops it and the
object does not remain there.

The situation is far worse when he drags the object across several pages: In
such cases, often the object simply vanishes from the current page. It either
goes back to its original page, or even lands on a third page that has no
relation with the source or target pages. The poor user has to go hunting for
the object all over again.

To avoid such possibilities, provide an advance indication that the object will
land here. 

Sample methods (there could be several other ways to do this):
* In the DOTTED rectangle that is being dragged around, the outline becomes a
SOLID line.
* A green tick appears over the dotted rectangle if the target area is
acceptable to Writer; otherwise it is a red cross.
* The target area (especially when it is table/frame) gets highlighted (but
probably this indication won't work if the target is a page--It has no boundary
to highlight!)

Similar visual indications are used when ends of a connector snaps to objects in
PowerPoint.