DragCells
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Shows how to perform cell drag and drop operations within the grid.

The sample stores custom data objects in grid cells (unbound mode), and uses
a custom CellFactory to create visual representations for the cells in the
current ViewRange.

The data objects are stored in the grid itself, and are permanent; the 
visuals are created when cells become visible and are automatically
destroyed when the cells scroll out of view.

The sample uses a C1DragDropManager to handle the actual drag/drop operations.
When the user drops a cell in a new location, the sample moves the data
object from the original cell to the target cell:

	// move object to target cell 
	var oldRange = new CellRange(bdr);
	_flex[oldRange.Row, oldRange.Column] = null;
	_flex[ht.Row, ht.Column] = viewObject.DataObject;

The grid detects the change and updates the view automatically, removing
the original view object and creating a new one at the target location.