ZoomCell
------------------------------------------------------------------------
Zoom in on the selected cell.

The sample shows how to use the CellStyle.Render method to display the contents
of a cell using a given CellStyle into an arbitrary Graphics object.

Click on any cell to see a magnified view of the cell. The zoomed view will follow
the cursor as you move the selection with the arrow keys, and will go away when
you hit escape or move the focus to another control.