UX: Never show back button if less than current position

UX: Never show back button if less than current position

diff --git a/app/assets/javascripts/discourse/app/widgets/topic-timeline.js b/app/assets/javascripts/discourse/app/widgets/topic-timeline.js
index f5b6765..310a8a3 100644
--- a/app/assets/javascripts/discourse/app/widgets/topic-timeline.js
+++ b/app/assets/javascripts/discourse/app/widgets/topic-timeline.js
@@ -225,10 +225,11 @@ createWidget("timeline-scrollarea", {
 
     let showButton = false;
     const hasBackPosition =
+      position.lastRead &&
       position.lastRead > 3 &&
+      position.lastRead > position.current &&
       Math.abs(position.lastRead - position.current) > 3 &&
       Math.abs(position.lastRead - position.total) > 1 &&
-      position.lastRead &&
       position.lastRead !== position.total;
 
     if (hasBackPosition) {

GitHub sha: d067ee1c5a73bd71e0d054483f8140f623e946f1

This commit appears in #14730 which was approved by markvanlan. It was merged by eviltrout.