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
if ( index != -1 )
		{
			selection = new StructuredSelection( valueTable.getTable( )
					.getItem( index )
					.getData( ) );
		}
		else
		{
			selection = StructuredSelection.EMPTY;
		}
		valueTable.setSelection( selection );
		updateTableButtons( );
	}
	private boolean getProperty( String key )
	{
		return ( (Boolean) dirtyProperties.get( key ) ).booleanValue( );
	}
	private String format( String string )
	{
		if ( canBeNull( ) && string == null )
		{
			return LABEL_NULL;
		}
		if ( StringUtil.isBlank( string ) || formatCategroy == null )
		{
			return string;
		}
		try
		{
			String pattern = formatPattern;