diff --git a/libraries/src/Form/FormField.php b/libraries/src/Form/FormField.php
index 36d5677820155..96dd3fd3a7248 100644
--- a/libraries/src/Form/FormField.php
+++ b/libraries/src/Form/FormField.php
@@ -600,7 +600,14 @@ public function setup(\SimpleXMLElement $element, $value, $group = null)
 		$this->default = isset($element['value']) ? (string) $element['value'] : $this->default;
 
 		// Set the field default value.
-		$this->value = $value;
+		if ($element['multiple'] && is_string($value) && is_array(json_decode($value, true)))
+		{
+			$this->value = (array) json_decode($value);
+		}
+		else 
+		{
+			$this->value = $value;
+		}
 
 		foreach ($attributes as $attributeName)
 		{