[REF] *: BS4, adapt display classes

The system completely changed. I also had to adapt classes to new
screen breakpoints.

hidden/hide -> d-none
show -> d-block
hidden-xs -> d-none d-md-(block/inline/...)
hidden-sm -> d-md-none d-lg-(block/inline/...)
hidden-md -> d-lg-none d-xl-(block/inline/...)
hidden-lg -> d-xl-none
visible-xs-* -> d-* d-md-none
visible-sm-* -> d-none d-md-* d-lg-none
visible-md-* -> d-none d-lg-* d-xl-none
visible-lg-* -> d-none d-xl-*
hidden-print -> d-print-none
visible-print-* -> d-none d-print-*
...
and all possible combination of those had to be handled too.

1 files changed, 1 insertions, 1 deletions

diff --git a/addons/mass_mailing/static/src/js/mass_mailing_editor.js b/addons/mass_mailing/static/src/js/mass_mailing_editor.js
index c7070e61a31..ae38436ea2c 100644
--- a/addons/mass_mailing/static/src/js/mass_mailing_editor.js
+++ b/addons/mass_mailing/static/src/js/mass_mailing_editor.js
@@ -28,7 +28,7 @@ options.registry.sizing_x = options.Class.extend({
         this.isIMG = this.$target.is("img");
         if (this.isIMG) {
             this.$overlay.find(".o_handle.w").addClass("readonly");
-            this.$overlay.find(".oe_snippet_move, .oe_snippet_clone").addClass("hidden");
+            this.$overlay.find(".oe_snippet_move, .oe_snippet_clone").addClass('d-none');
         }
 
         var $body = $(document.body);