Update

resources/assets/dcat-admin/main.css

@@ -2037,7 +2037,7 @@ div.layui-layer-btn{
 
 .fields-group label.asterisk:before {
     content: "*";
-    margin:0 5px 0 0;
+    margin:0 3px 0 0;
     font-weight:bold;
     color:#dd4b39
 }

src/Form/Field/Tree.php

@@ -226,6 +226,7 @@ class Tree extends Field
 
         $checkboxes->style('primary');
         $checkboxes->inline();
+        $checkboxes->circle(false);
         $checkboxes->options([
             1 => trans('admin.selectall'),
             2 => trans('admin.expand')