hide add_child for root node (#13444)

diff --git a/erpnext/accounts/doctype/cost_center/cost_center_tree.js b/erpnext/accounts/doctype/cost_center/cost_center_tree.js
index f409d64..5043669 100644
--- a/erpnext/accounts/doctype/cost_center/cost_center_tree.js
+++ b/erpnext/accounts/doctype/cost_center/cost_center_tree.js
@@ -48,5 +48,10 @@
 		}, __('Budget'));
 
 	},
+	onrender: function(node) {
+		if(node.is_root){
+			node.hide_add = true;
+		}
+	}
 
 }
\ No newline at end of file