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
columnChooser = new Combo( composite, SWT.BORDER | SWT.READ_ONLY );
		columnChooser.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		columnChooser.addSelectionListener( new SelectionAdapter( ) {
			public void widgetDefaultSelected( SelectionEvent e )
			{
				updateButtons( );
			}
		} );
		createLabel( composite, null );
		createLabel( composite, LABEL_SELECT_DISPLAY_TEXT );
		displayTextChooser = new Combo( composite, SWT.BORDER | SWT.READ_ONLY );
		displayTextChooser.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		createLabel( composite, null );
		createDefaultEditor( );
		listLimit.setEditable( true );
	}
	private void createDefaultEditor( )
	{
		createLabel( valueArea, LABEL_DEFAULT_VALUE );
		defaultValueEditor = new Text( valueArea, SWT.BORDER );
		defaultValueEditor.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		defaultValueEditor.addModifyListener( new ModifyListener( ) {
			public void modifyText( ModifyEvent e )
			{
				defaultValue = UIUtil.convertToModelString( defaultValueEditor.getText( ),
						false );
				if ( isStatic( ) )
				{
					refreshValueTable( );
				}