diff --git a/addons/web/static/src/legacy/scss/datepicker.scss b/addons/web/static/src/legacy/scss/datepicker.scss
index af8d5980bed..7493c992eef 100644
--- a/addons/web/static/src/legacy/scss/datepicker.scss
+++ b/addons/web/static/src/legacy/scss/datepicker.scss
@@ -38,13 +38,8 @@
 div.dropdown-menu.bootstrap-datetimepicker-widget {
     min-width: 0;
     padding: 0;
-    border-top: 0;
-
-    &.bottom {
-        &:before, &:after {
-            transform: translateY(1px);
-        }
-    }
+    border: 1px solid $dropdown-border-color;
+    overflow: visible; // Needed until dropdown-menu will be 'hoverflow:hidden'
 
     // Need to put datetimepicker widget above everything else
     z-index: $zindex-modal + 1;
@@ -67,6 +62,10 @@ div.dropdown-menu.bootstrap-datetimepicker-widget {
         }
     }
 
+    thead tr:nth-child(1) th {
+        border-top: 0;
+    }
+
     thead tr:nth-child(2) th {
         height: 20px;
         line-height: 20px;
diff --git a/addons/web/static/src/legacy/scss/ui.scss b/addons/web/static/src/legacy/scss/ui.scss
index 6f875ed5cbd..323c5d75ecf 100644
--- a/addons/web/static/src/legacy/scss/ui.scss
+++ b/addons/web/static/src/legacy/scss/ui.scss
@@ -2,7 +2,8 @@
 $bs-datetimepicker-active-bg: $o-brand-odoo;
 $bs-datetimepicker-active-color: $white;
 $bs-datetimepicker-text-shadow: 0 1px 0 rgba(0, 0, 0, 0.25);
-$bs-datetimepicker-secondary-border-color-rgba: $border-color;
+$bs-datetimepicker-secondary-border-color: $dropdown-border-color;
+$bs-datetimepicker-secondary-border-color-rgba: $dropdown-border-color;
 
 .o_hidden {
     display: none!important;