--- loncom/interface/lonhelp.pm	2017/04/01 13:55:32	1.46
+++ loncom/interface/lonhelp.pm	2023/04/06 17:36:12	1.49
@@ -1,6 +1,6 @@
 # The LearningOnline Network with CAPA
 #
-# $Id: lonhelp.pm,v 1.46 2017/04/01 13:55:32 raeburn Exp $
+# $Id: lonhelp.pm,v 1.49 2023/04/06 17:36:12 raeburn Exp $
 #
 # .tex help system web server handler
 #
@@ -71,9 +71,17 @@ sub servetext {
                                            search  => 'Search LON-CAPA help',
                                            query   => 'Search',
                                         );
+    my $goback;
+    if ((($env{'request.lti.login'}) && ($env{'request.lti.target'} eq 'iframe')) ||
+        (($env{'request.deeplink.login'}) && ($env{'request.deeplink.target'} eq '_self'))) {
+        my $backicon = &Apache::loncommon::lonhttpdurl($r->dir_config('lonIconsURL').'/').'clickhere.gif';
+        $goback = '<a href="javascript:history.go(-1);" class="LC_menubuttons_link" title="Go Back">'.
+                  '<img src="'.$backicon.'" alt="'.&mt('Go Back').'" class="LC_icon" border="0" />'.
+                  '</a>&nbsp;';
+    }
     $r->print(<<HEADER);
     <h3 style="font: sans-serif"><img align="right" alt="help logo"
-    src="/adm/help/gif/lonhelpheader.gif" />$lt{'header'}</h3><hr />
+    src="/adm/help/gif/lonhelpheader.gif" />$goback$lt{'header'}</h3><hr />
     <!-- BEGIN -->
 HEADER
     if ($is_mobile) {
@@ -246,8 +254,10 @@ sub handler {
                       };
      }
      my $firstfile;
+     $env{'form.texengine'} = 'tth';
      my $start_page=
 	 &Apache::loncommon::start_page('LON-CAPA Help',undef,$starthash);
+     delete($env{'form.texengine'});
      my $text='';
      my $uri = $r->uri;
      if ($env{'form.searchterm'}=~/\w/) {