We've run into an issue on several sites that use this module with the Simline template portfolio system when trying to edit Portfolio Items. The following warning appears:

[Warning] Invalid argument supplied for foreach()
/container/application/public/silverstripe-simplelistfield/forms/SimpleListField/SimpleListField.php:144

We are then unable to edit or save any changes to the Portfolio Item.

The problem is in the preloadScenarios function in SimpleListField.php and it appears that the variable $scenarios is not coming through as an array.

public static function preloadScenarios(){
		if(self::$preloaded_scenario === false){
			self::$preloaded_scenario = true;
			
			$scenarios = Config::inst()->get('SimpleListField', 'Scenarios');
			
			foreach($scenarios as $key => $val){
				if( isset($val['preload']) && $val['preload'] ){
					self::$scenarios[$key] = $val;
				}
			}
		}
	}

There doesn't seem to be any need to preload Scenarios for the module to work so we've been able to get around it by simply commenting out line 20 of SimpleListField.php so the function is not called. However this isn't exactly a fix.

My guess is that the scenarios for preload should be defined in a config file somewhere but there are no instructions on how to do this that I can see.

SimpleListField invalid argument warning.docx