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
{
					case 0 :
						defaultValue = null;
						break;
					case 1 :
						defaultValue = Boolean.toString( true );
						break;
					case 2 :
						defaultValue = Boolean.toString( false );
						break;
				}
			}
		} );
	}
	private void switchToList( )
	{
		createLabel( valueArea, LABEL_VALUES );
		Composite tableArea = new Composite( valueArea, SWT.NONE );
		tableArea.setLayout( UIUtil.createGridLayoutWithoutMargin( ) );
		tableArea.setLayoutData( new GridData( GridData.FILL_BOTH ) );
		Table table = new Table( tableArea, SWT.SINGLE
				| SWT.FULL_SELECTION
				| SWT.BORDER );
		table.setLayoutData( new GridData( GridData.FILL_BOTH ) );
		table.setLinesVisible( true );
		table.setHeaderVisible( true );
		table.addKeyListener( new KeyAdapter( ) {
			/**
			 * @see org.eclipse.swt.events.KeyAdapter#keyReleased(org.eclipse.swt.events.KeyEvent)
			 */