config and css for term-reference-tree track_list

config/sync/core.entity_form_display.node.materiau.default.yml

@@ -298,6 +298,8 @@ content:
       start_minimized: true
       select_parents: true
       cascading_selection: 0
+      track_list: true
+      track_list_order: true
       max_depth: 0
       leaves_only: false
     third_party_settings: {  }

web/themes/custom/matminimal/css/matminimal.css

@@ -42,3 +42,22 @@
   min-height: 0;
   padding: 0.2em 0.4em 0.2em 0.5em;
 }
+
+.field--widget-term-reference-tree fieldset.form-wrapper{
+  display:block;
+}
+.term-reference-tree{
+  display:block;
+}
+.term-reference-tree>ul, .term-reference-tree aside.term-reference-tree-track-list{
+  display:inline-block;
+  vertical-align:top;
+}
+.term-reference-tree>ul{
+  padding-right:1em;
+  min-width:45%;
+}
+.term-reference-tree aside.term-reference-tree-track-list{
+  border-left:1px solid #aaa;
+  padding-left:1em;
+}