diff --git a/theme/standard/styles_layout.css b/theme/standard/styles_layout.css
index 39114f0ff8b..d5eb55039ba 100644
--- a/theme/standard/styles_layout.css
+++ b/theme/standard/styles_layout.css
@@ -2811,7 +2811,6 @@ div.allcoursegrades {
 /* gradebook edit tree */
 
 .grade-edit-tree .gradetreebox {
-  width:70%;
   margin-left:auto;
   margin-right:auto;
   margin-top:10px;
@@ -2878,6 +2877,10 @@ div.allcoursegrades {
   margin-top: 7px;
 }
 
+.gradetreebox table.simple {
+  width: 70%;
+}
+
 /***
  *** Login
  ***/
@@ -5848,4 +5851,4 @@ wikiadminactions {
   bottom:-10px;
   left:-10px;
   background-position:0px 100%;
-}
\ No newline at end of file
+}