From 144400df4b58b2324d88a0cc00a80c455da8732a Mon Sep 17 00:00:00 2001
From: Tim Otten <totten@civicrm.org>
Date: Wed, 6 Oct 2021 00:26:58 -0700
Subject: [PATCH] message_admin (Preview) - Fix loop-around on "<<Previous"
 button

Before: If you open the new "Preview" pane and press the "<<Previous"
button, it loops to invalid position `-1`.

After: Loop-around works in both directions.
---
 ext/message_admin/ang/crmMsgadm/Preview.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ext/message_admin/ang/crmMsgadm/Preview.js b/ext/message_admin/ang/crmMsgadm/Preview.js
index bf4a32ff9c..f35afbb279 100644
--- a/ext/message_admin/ang/crmMsgadm/Preview.js
+++ b/ext/message_admin/ang/crmMsgadm/Preview.js
@@ -10,7 +10,7 @@
     $ctrl.revisionId = parseInt(_.findKey(model.revisions, {name: model.revisionName}));
     $ctrl.formatId = parseInt(_.findKey(model.formats, {name: model.formatName}));
     $ctrl.cycle = function(idFld, listFld, delta){
-      $ctrl[idFld] = ($ctrl[idFld] + delta) % model[listFld].length;
+      $ctrl[idFld] = ($ctrl[idFld] + delta + model[listFld].length) % model[listFld].length;
     };
 
     $ctrl.adhocExample = {};
-- 
2.25.1