diff --git a/src/less/resource/background.less b/src/less/resource/background.less
index 446b250c6..21c157665 100644
--- a/src/less/resource/background.less
+++ b/src/less/resource/background.less
@@ -70,30 +70,6 @@
   }
 }
 
-.ztree.hack li span.button.chk.checkbox_false_part {
-  .imagePath(@icon-half-select);
-}
-
-.ztree.hack li span.button.chk.checkbox_false_part_focus {
-  .imagePath(@icon-half-select);
-}
-
-.ztree.hack li span.button.chk.checkbox_true_full {
-  .imagePath(@icon-checkbox-active);
-}
-
-.ztree.hack li span.button.chk.checkbox_true_full_focus {
-  .imagePath(@icon-checkbox-active);
-}
-
-.ztree.hack li span.button.chk.checkbox_true_part {
-  .imagePath(@icon-half-select);
-}
-
-.ztree.hack li span.button.chk.checkbox_true_part_focus {
-  .imagePath(@icon-half-select);
-}
-
 .ztree li span.button.root_open {
   .image2xPath(@icon-tree-expand-type1);
 }