reuse div with initials when rendering

CHANGELOG

 smasch (1.0.1-1) stable; urgency=low
 
+  * bug fix: worker initials were not visible after changing appointments
+    calendar view from month to week (#377)
+
  -- Piotr Gawron <piotr.gawron@uni.lu>  Mon, 15 Mar 2021 14:00:00 +0200
 
 smasch (1.0.0-1) stable; urgency=low

smash/web/templates/appointments/index.html

@@ -117,7 +117,10 @@
                 startParam: "start_date",
                 endParam: "end_date",
                 dayRender: function (date, cell) {
-                    var element = document.createElement("div");
+                    var element = dayHeaders[$(cell[0]).attr("data-date")];
+                    if (element === undefined) {
+                        element = document.createElement("div");
+                    }
                     cell[0].appendChild(element);
                     dayHeaders[$(cell[0]).attr("data-date")] = element;
                 },
@@ -146,7 +149,7 @@
                     if (event.status) {
                         content += '<li>Status: ' + event.status + '</li>'
                     }
-                    
+
                     content += "</ul>";
                     $(element).popover({
                         title: event.title,