Bug 161191 Null is inserted when drag columns to query text with ctrl key pressed
Description: Null is inserted when drag columns to query text with ctrl key pressed Steps to reproduce: 1. New a data source. 2. New a dataset. 3. Press and hold ctrl key, select OFFICECODE and CITY columns, drag to query text. Expected result: "CLASSICMODELS.OFFICES.OFFICECODE,CLASSICMODELS.OFFICES.CITY" is inserted in query text. Actual result: "null,CLASSICMODELS.OFFICES.OFFICECODE,CLASSICMODELS.OFFICES.CITY" is inserted
data/org.eclipse.birt.report.data.oda.jdbc.ui/src/org/eclipse/birt/report/data/oda/jdbc/ui/editors/SQLDataSetEditorPage.java
}
		if ( hasNonSystemTable )
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	
	/**
	 * Sets the Root Element of the Available Data Sources This is usually the
	 * Name of the Catalog of the Database
	 */
	protected void setRootElement( )
	{
		rootNode = new TreeItem( availableDbObjectsTree, SWT.NONE );
		rootNode.setImage( dataBaseImage );
		DataSourceDesign dataSourceHandle = this.getDataSetDesign( )
				.getDataSourceDesign( );
		rootNode.setText( dataSourceHandle.getName( ) );
	}
	
	/**
	 * Remove all available db objects
	 * 
	 */
	private void RemoveAllAvailableDbObjects( )
	{