This should be the real fix for the even recursion

There's a bogus duplicated mouse event for a.silence-duration-btn, which I added to fix css issues, get rid of it and replace with proper css selectors. And with that drop the event.stopPropagation call as it shouldn't be needed anymore

assets/static/base.css

@@ -436,8 +436,15 @@ table.table.silence-label-selects > tbody > tr > td {
   font-size: 2em;
 }
 .silence-duration-btn:hover {
+  color: #fff;
   background: #eee;
 }
+.silence-duration-btn:focus {
+  color: #18bc9c;
+}
+.silence-duration-btn:focus:hover {
+  color: #fff;
+}
 .silence-duration-btn > i {
   pointer-events: none;
 }

assets/static/ui.js

@@ -205,9 +205,6 @@ var UI = (function(params) {
       }
       $("#endsAt").data('DateTimePicker').date(endsAt);
       silenceFormCalculateDuration();
-
-      // prevent recursive events
-      event.stopPropagation();
     };
 
 
@@ -313,7 +310,6 @@ var UI = (function(params) {
                     $("#endsAt").data('DateTimePicker').minDate(startsAt);
                   });
                   modal.on("click", "a.silence-duration-btn", silenceFormUpdateDuration);
-                  modal.on("mousedown", "a.silence-duration-btn", false);
                   silenceFormCalculateDuration();
                 }
             });