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
defaultValue = inputParameter.getDefaultValue( );
		
		if ( inputParameter.getPropertyHandle( ScalarParameterHandle.LIST_LIMIT_PROP )
				.isSet( ) )
		{
			listLimit.setText( String.valueOf( inputParameter.getListlimit( ) ) );
		}
		changeDataType( );
		dataTypeChooser.setText( dataType.findChoice( inputParameter.getDataType( ) )
				.getDisplayName( ) );
		switchParamterType( );
		loading = false;
		return true;
	}
	private void initValueArea( )
	{
		if ( isStatic( ) )
		{
			if ( DesignChoiceConstants.PARAM_CONTROL_CHECK_BOX.equals( getSelectedControlType( ) ) )
			{