Bug 192349 The column selected disappears when you reclick the downward arrow [0001]
Description: The column selected disappears when you reclick the downward arrow. Build number: 2.2.0.v20070613-1211 Steps to reproduce: 1, New a table binding to a data set, add an Aggregation, select one column from the "Data Field" dropdown list, click the downward arrow again. Expected result: The column selected is still there. Actual result: The column selected disappears. Error log: N/A
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/internal/ui/dialogs/BindingDialogHelper.java
public void widgetSelected( SelectionEvent e )
			{
				String expr = getColumnBindingExpressionByName( cmbDataField.getText( ) );
				if ( expr != null )
				{
					cmbDataField.setText( expr );
				}
				else
				{
					cmbDataField.setText( "" ); 
				}
			}
		} );
		argsComposite = new Composite( composite, SWT.NONE );
		GridData gridData = new GridData( GridData.FILL_HORIZONTAL
				| GridData.GRAB_HORIZONTAL );
		gridData.horizontalSpan = 3;
		gridData.exclude = true;
		argsComposite.setLayoutData( gridData );
		GridLayout layout = new GridLayout( );
		
		layout.marginWidth = layout.marginHeight = 0;
		layout.numColumns = 3;
		argsComposite.setLayout( layout );
		new Label( composite, SWT.NONE ).setText( FILTER_CONDITION );
		txtFilter = new Text( composite, SWT.BORDER );
		txtFilter.setLayoutData( new GridData( GridData.FILL_HORIZONTAL
				| GridData.GRAB_HORIZONTAL ) );
		createExpressionButton( composite, txtFilter );
		txtFilter.addModifyListener( new ModifyListener( ) {