Ensure that the start and end date should be deleted when clear the selection for pgAgent Job. Fixes #3645

docs/en_US/release_notes.rst

@@ -11,6 +11,7 @@ notes for it.
 .. toctree::
    :maxdepth: 1
 
+   release_notes_4_21
    release_notes_4_20
    release_notes_4_19
    release_notes_4_18

docs/en_US/release_notes_4_21.rst

@@ -0,0 +1,20 @@
+************
+Version 4.21
+************
+
+Release date: 2020-04-30
+
+This release contains a number of bug fixes and new features since the release of pgAdmin4 4.20.
+
+New features
+************
+
+
+Housekeeping
+************
+
+
+Bug fixes
+*********
+
+| `Issue #3645 <https://redmine.postgresql.org/issues/3645>`_ -  Ensure that the start and end date should be deleted when clear the selection for pgAgent Job.

web/pgadmin/static/js/backform.pgadmin.js

@@ -2977,7 +2977,7 @@ define([
 
         data.cId = data.cId || _.uniqueId('pgC_');
 
-        if (!data.disabled) {
+        if (!data.disabled && data.mode != 'properties') {
           data.placeholder = data.placeholder || this.defaults.placeholder;
         }
 

web/pgadmin/static/js/backgrid.pgadmin.js

@@ -1851,15 +1851,11 @@ define([
       this.$el.datetimepicker('destroy');
       this.is_closing = false;
 
-      if (_.isUndefined(newValue)) {
-        model.trigger('backgrid:error', model, column, val);
-      } else {
       model.set(column.get('name'), newValue);
       let command = new Backgrid.Command(ev);
       setTimeout(() => {
         model.trigger('backgrid:edited', model, column, command);
       }, 20);
-      }
     },
   });