Fix the double click on the ITransact submit button. Fixes bug #11362.

docs/changelog/7.x.x.txt

@@ -1,4 +1,5 @@
 7.8.11
+ - fixed #11362: Unable to checkout with ITransact plugin
 
 7.8.10
  - fixed #11332: Pagination in webgui.org forum urls

lib/WebGUI/Shop/PayDriver/ITransact.pm

@@ -809,7 +809,7 @@ sub www_getCredentials {
 
     $var->{checkoutButton} = WebGUI::Form::submit($session, {
         value => $i18n->get('checkout button', 'Shop'),
-        extras => 'onclick="this.disabled=true;"',
+        extras => 'onclick="this.disabled=true;this.form.submit(); return false;"',
     });
 
     my $template = WebGUI::Asset::Template->new($session, $self->get("credentialsTemplateId"));