Pull request #2555: 无JIRA任务 chore: bugfix

Merge in VISUAL/fineui from ~GUY/fineui:master to master

* commit '64d7823d3db81133a59c9d5f28df7f1f97512658':
  chore: bugfix

src/less/base/tree/tree.expander.less

@@ -13,6 +13,9 @@
 }
 
 .bi-theme-dark {
+  .bi-tree-expander-popup.line:before {
+    border-left: 1px dashed @color-bi-border-tree-expander-popup-line-theme-dark;
+  }
   .bi-tree-expander-popup.line.solid:before {
     border-left: 1px solid @color-bi-border-tree-expander-popup-line-theme-dark;
   }