Bug 116180 [SPM]Dataset can not be previewed in report designer on Mac
Description: Pull a dataset into the layout, preview in designer there is anothing displayed. Steps: 1, Create a sample datasource. create a dataset with sql statement "select * from CLASSICMODELS.EMPLOYEES" 2, Pull the dataset to the layout of the designer. 3, Preview, there is nothing displayed.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dnd/DesignElementDragAdapter.java
if ( objects.length == 1 )
			{
				return true;
			}
			else
			{
				return false;
			}
		}
		
		Class type = null;
		for ( int i = 0; i < objects.length; i++ )
		{
			if ( type == null )
				type = objects[i].getClass( );
			else if ( !type.equals( objects[i].getClass( ) ) )
				return false;
		}
		return true;
	}
	/**
	 * Returns viewer
	 * 
	 * @return viewer
	 */
	protected StructuredViewer getViewer( )
	{
		return viewer;
	}
}