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
SQLUtility.getTailoredSearchText( null ) );
						TreeItem[] items = item.getItems( );
						if ( items != null )
						{
							for ( int i = 0; i < items.length; i++ )
							{
								items[i].dispose( );
							}
						}
						Utility.createTreeItems( item,
								columnList,
								SWT.NONE,
								columnImage );
					}
				}
			}
		} );
	}
	
	/**
	 * Adds drag support to tree..Must set tree before execution.
	 */
	public void addDragSupportToTree( )
	{
		DragSource dragSource = new DragSource( availableDbObjectsTree, DND.DROP_COPY );
		dragSource.setTransfer( new Transfer[]{TextTransfer.getInstance( )} );
		dragSource.addDragListener( new DragSourceAdapter( ) {
			public void dragStart( DragSourceEvent event )
			{
				TreeItem[] selection = availableDbObjectsTree.getSelection( );