isSingleton was not ever in the editSave form for the Workflow!

docs/changelog/7.x.x.txt

@@ -22,6 +22,8 @@
         http://www.plainblack.com/bugs/tracker/sqlform---cannot-add-new-asset-revisited#barqLwFe3LPODb4Mksc6ZA
  - fix: Fixed a bug where $session->form->param() would return params twice. 
  	(Martin Kamerbeek / Oqapi)
+ - fix: Can't set workflow to singleton (perlDreamer Consulting, LLC)
+        http://www.plainblack.com/bugs/tracker/cant-set-workflow-to-singleton
 
 7.3.13
  - fix: Stale pages after user login

lib/WebGUI/Operation/Workflow.pm

@@ -247,6 +247,7 @@ sub www_editWorkflowSave {
 	my $workflow = WebGUI::Workflow->new($session, $session->form->param("workflowId"));
 	$workflow->set({
 		enabled     => $session->form->get("enabled",     "yesNo"),
+		isSingleton => $session->form->get("isSingleton", "yesNo"),
 		isSerial    => $session->form->get("isSerial",    "yesNo"),
 		title       => $session->form->get("title"),
 		description => $session->form->get("description", "textarea"),