Bug 160429 Drag the datasource and dataset and produce an error gradation in data explorer
Details: Drag the datasource and dataset and produce an error gradation in data explorer Step: 1.New 4 datasource named d1, d2, d3, d4. 2.Drag the datasource in data explorer to change the gradation. (1) Drag d1 between d2 and d3. (2) Drag d2 between d3 and d4. (3) Drag d4 between d2 and d3. (4) Drag d4 to the top. (5) Drag d3 between d1 and d2. (6) Drag d3 to the top. Actual result: (1) d1 will be move to bottom. (2) d2 will be move to bottom. (3) d4 will not be move to anywhere. (4) d4 will not be move to anywhere. (5) d3 will be move to bottom. (6) d3 will be move to bottom. Excepted result: The datasource will be move to the correct station.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
/**
	 * Returns the flatten Parameters/ParameterGroups of the design. This method
	 * put all Parameters and ParameterGroups into a list then return it. The
	 * return list is sorted by on the display name of the parameters.
	 * 
	 * @return the sorted, flatten parameters and parameter groups.
	 */
	public List getFlattenParameters( )
	{
		ArrayList list = new ArrayList( );
		SlotHandle slotHandle = getParameters( );
		Iterator it = slotHandle.iterator( );
		while ( it.hasNext( ) )
		{
			DesignElementHandle h = (DesignElementHandle) it.next( );
			list.add( h );
			if ( h instanceof ParameterGroupHandle )
			{
				addParameters( list, (ParameterGroupHandle) h );
			}
		}
		DesignElementHandle.doSort( list );
		return list;
	}
	/**
	 * Returns an external file that provides help information for the report.
	 * 
	 * @return the name of an external file
	 */
	public String getHelpGuide( )