Merge pull request #332 from skeeks-semenov/master

Enhance Select2 required attribute validation when used with model

src/Select2.php

@@ -459,7 +459,14 @@ protected function isRequired()
         $validators = $this->model->getActiveValidators($this->attribute);
         foreach ($validators as $validator) {
             if ($validator instanceof RequiredValidator) {
-                return true;
+                if (is_callable($validator->when)) {
+                    if (call_user_func($validator->when, $this->model, $this->attribute)) {
+                        return true;
+                    }
+                } else {
+                    return true;
+                }
+
             }
         }
         return false;