Always use multipart/form-data for all forms. Allows using file fields in inline forms

flask_admin/form.py

@@ -24,6 +24,7 @@ class BaseForm(wtf.Form):
     def has_file_field(self):
         """
             Return True if form contains at least one FileField.
+            Does not check for child form fields.
         """
         # TODO: Optimize me
         for f in self:

flask_admin/templates/admin/lib.html

@@ -114,7 +114,7 @@
 {% endmacro %}
 
 {% macro form_tag() %}
-    <form action="" method="POST" class="form-horizontal"{% if form.has_file_field %} enctype="multipart/form-data"{% endif %}>
+    <form action="" method="POST" class="form-horizontal" enctype="multipart/form-data">
       <fieldset>
         {{ caller() }}
       </fieldset>