Bug 151960 Library element popup menu display is wrong.
1:Creat a libray, add a table to this libray. 2:public this library. 3:Creat a report design. 4:Open the library explore, drag the table to the layout editor. 5:Select the table row, copy the selection row. 6:Select other row, clik the right button of the mouse to popup the menu . The result:Paste action and insert copied column action is highlight.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ColumnBandAdapter.java
* @param columnIndex
	 *            the column number
	 * @param mustBeStartPosition
	 *            <code>true</code> if it is. Otherwise <code>false</code>.
	 * @return a new cell instance
	 */
	private CellHandle getCellsInRow( RowHandle row, int columnIndex,
			boolean mustBeStartPosition )
	{
		SlotHandle cells = row.getCells( );
		for ( int i = 0; i < cells.getCount( ); i++ )
		{
			CellHandle cell = (CellHandle) cells.get( i );
			int cellColumnIndex = getCellPosition( cell );
			if ( cellColumnIndex == columnIndex )
				return cell;
			if ( !mustBeStartPosition && cellColumnIndex < columnIndex
					&& cellColumnIndex + cell.getColumnSpan( ) >= columnIndex )
				return cell;
		}
		return null;
	}
	/**
	 * Returns a list containing rows.
	 * 
	 * @return a list containing rows.
	 */
	abstract protected List getRowContainerSlots( );
}