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
super.setVisible( visible );
		getControl( ).setFocus( );
	}
    
	/**
	 * Prepare UI when pageActivated event is invoked Following things will be
	 * done: Set StyledText content Set StyledText as focus
	 * 
	 */
	private void prepareUI( )
	{
		StyledText styledText = viewer.getTextWidget( );
		String queryText = styledText.getText( );
		String extensionId = this.getDataSetDesign( )
				.getOdaExtensionDataSetId( );
		this.formerQueryTxt = queryText;
		if ( queryText != null
				&& queryText.equalsIgnoreCase( SQLUtility.getQueryPresetTextString( extensionId ) ) )
		{
			String[] lines = SQLUtility.getQueryPresetTextArray( extensionId );
			if ( lines != null && lines.length > 0 )
				styledText.setSelection( lines[0].length( ) + 1,
						lines[0].length( ) + 1 );
		}
		styledText.setFocus( );
	}
	
	/**
	 * return the query text. If the query text is empty then return the
	 * pre-defined pattern