allow empty select-value for panel.customer_hide_options

Signed-off-by: Michael Kaufmann (d00p) <d00p@froxlor.org>

actions/admin/settings/100.panel.php

@@ -234,6 +234,7 @@ return array(
 					'type' => 'option',
 					'default' => '',
 					'option_mode' => 'multiple',
+					'option_emptyallowed' => true,
 					'option_options' => array(
 						'email'                       => $lng['menue']['email']['email'],
 						'mysql'                       => $lng['menue']['mysql']['mysql'],

lib/functions/formfields/option/function.validateFormFieldOption.php

@@ -40,6 +40,9 @@ function validateFormFieldOption($fieldname, $fielddata, $newfieldvalue)
 	}
 	else
 	{
+		if (isset($fielddata['option_emptyallowed']) && $fielddata['option_emptyallowed']) {
+			return true;
+		}
 		return 'not in option';
 	}
 }