Bug 153387 Database item can't be dragged and dropped onto editor field
Steps to reproduce: 1.Start up BIRT in Mac OS X; 2.File->New->Project; 3.File->New->Report Design; 4.In Data Explorer, create a New Data Source, and choose "Classic Models Inc. Sample DataBase", press "Next" and then press "finish"; 5.In Data Explorer, create a New Data Set, press "Next"; 6.In the popup window, expand the "CLASSICMODELS", select and drag a item onto the editor field at right side.
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
{
		
		DataSourceDesign curDataSourceDesign = this.getDataSetDesign( )
				.getDataSourceDesign( );
		if ( curDataSourceDesign != prevDataSourceDesign )
		{
			RemoveAllAvailableDbObjects( );
			resetJdbcInfo( curDataSourceDesign );
			enableSchemaComponent( isSchemaSupported );
			setRootElement( );
			sourceViewerConfiguration.getContentAssistProcessor( )
					.setDataSourceHandle( curDataSourceDesign );
			populateAvailableDbObjects( );
			prevDataSourceDesign = curDataSourceDesign;
		}
	}	
	
	/**
	 * 
	 */
	private void addFetchDbObjectListener( )
	{
		availableDbObjectsTree.addListener( SWT.Expand, new Listener( ) {
			/*
			 * @see org.eclipse.swt.widgets.Listener#handleEvent(org.eclipse.swt.widgets.Event)
			 */
			public void handleEvent( final Event event )
			{
				TreeItem item = (TreeItem) event.item;
				BusyIndicator.showWhile( item.getDisplay( ), new Runnable( ) {