Bug 146796 Error message pop up if display text contain non-digital char when add next item
Description: In decimal type parameter creation,display type is "list box", Error message pop up if "display text" contain non-digital char when add next item. Steps: 1.Create a new decimal parameter 2.Set display type as "list box" 3.Input one item: value:1, display text:test 4.Input another item: Value:2 Actual result: error message pop up: The display text already exists! Expected result: Input item succussfully.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
super( parentShell, title );
	}
	protected Control createDialogArea( Composite parent )
	{
		Composite composite = (Composite) super.createDialogArea( parent );
		createPropertiesSection( composite );
		createMoreOptionSection( composite );
		UIUtil.bindHelp( parent, IHelpContextIds.PARAMETER_DIALOG_ID );
		return composite;
	}
	private void createPropertiesSection( Composite composite )
	{
		Group propertiesSection = new Group( composite, SWT.NONE );
		propertiesSection.setText( GROUP_PROPERTIES );
		propertiesSection.setLayout( new GridLayout( 2, false ) );
		propertiesSection.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		createLabel( propertiesSection, LABEL_NAME );
		nameEditor = new Text( propertiesSection, SWT.BORDER );
		nameEditor.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		nameEditor.addModifyListener( new ModifyListener( ) {
			public void modifyText( ModifyEvent e )
			{
				updateMessageLine( );
			}
		} );
		createLabel( propertiesSection, LABEL_PROMPT_TEXT );
		promptTextEditor = new Text( propertiesSection, SWT.BORDER );
		promptTextEditor.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		createLabel( propertiesSection, LABEL_PARAM_DATA_TYPE );
		dataTypeChooser = new Combo( propertiesSection, SWT.READ_ONLY