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
{
						return;
					}
				}
				else
					return;
			}
		}
		
		 
		
		RemoveAllAvailableDbObjects( );
		setRootElement( );
		setRefreshInfo( );
		if ( isSchemaSupported )
		{
			populateSchemaList( );
		}
		else
		{
			populateTableList( );
		}
		addFetchDbObjectListener( );  
		
		
		if( rootNode != null )
		{
			selectNode(rootNode);
		}
	}