diff --git a/lib/x11/corereqs.js b/lib/x11/corereqs.js
index e2fcee4..95dfd04 100644
--- a/lib/x11/corereqs.js
+++ b/lib/x11/corereqs.js
@@ -294,7 +294,9 @@ module.exports = {
 
    // TODO: test
    DeleteProperty: [
-       [ 'CxLLL', [19, 3] ] // wid, propNameAtom
+       function(wid, prop) {
+           return [ 'CxSLL', [19, 3, wid, prop] ];
+       }
    ],
 
    GetProperty: [