diff --git a/src/pretix/control/forms/event.py b/src/pretix/control/forms/event.py
index 068d306d42..79b7b4b2d5 100644
--- a/src/pretix/control/forms/event.py
+++ b/src/pretix/control/forms/event.py
@@ -1635,10 +1635,15 @@ class MailSettingsForm(FormPlaceholderMixin, SettingsForm):
             self._set_field_placeholders(k, v, rich=k.startswith('mail_text_') and k not in self.plain_rendering)
 
         for k, v in list(self.fields.items()):
-            if k.endswith('_attendee') and not event.settings.attendee_emails_asked:
-                # If we don't ask for attendee emails, we can't send them anything and we don't need to clutter
-                # the user interface with it
-                del self.fields[k]
+            if k.endswith('_attendee'):
+                if not event.settings.attendee_emails_asked:
+                    # If we don't ask for attendee emails, we can't send them anything and we don't need to clutter
+                    # the user interface with it
+                    del self.fields[k]
+                elif 'subject' in k and k.replace("subject", "send") in self.fields:
+                    v.widget.attrs["data-display-dependency"] = f'#id_{k.replace("subject", "send")}'
+                elif 'text' in k and k.replace("text", "send") in self.fields:
+                    v.widget.attrs["data-display-dependency"] = f'#id_{k.replace("text", "send")}'
 
 
 class TicketSettingsForm(SettingsForm):
diff --git a/src/pretix/static/pretixcontrol/js/ui/main.js b/src/pretix/static/pretixcontrol/js/ui/main.js
index 7ebefa0bbd..5dee045a8f 100644
--- a/src/pretix/static/pretixcontrol/js/ui/main.js
+++ b/src/pretix/static/pretixcontrol/js/ui/main.js
@@ -401,6 +401,9 @@ var form_handlers = function (el) {
                 if (tagName !== "div" && tagName !== "button") {
                     $toggling = dependent.closest('.form-group');
                 }
+                if ($toggling.find(".has-error").length > 0) {
+                    enabled = true;  // Don't hide error message that makes form unsubmittable
+                }
                 if (ev) {
                     if (enabled) {
                         $toggling.stop().slideDown();