diff --git a/dlls/jscript/dispex.c b/dlls/jscript/dispex.c
index 7d5ebe2c863..aa81de7ad75 100644
--- a/dlls/jscript/dispex.c
+++ b/dlls/jscript/dispex.c
@@ -656,7 +656,13 @@ static HRESULT prop_put(jsdisp_t *This, dispex_prop_t *prop, jsval_t val)
             TRACE("no prop_put\n");
             return S_OK;
         }
-        return This->builtin_info->prop_put(This, prop->u.id, val);
+        hres = This->builtin_info->prop_put(This, prop->u.id, val);
+        if(hres != S_FALSE)
+            return hres;
+        prop->type = PROP_JSVAL;
+        prop->flags = PROPF_ENUMERABLE | PROPF_CONFIGURABLE | PROPF_WRITABLE;
+        prop->u.val = jsval_undefined();
+        break;
     default:
         ERR("type %d\n", prop->type);
         return E_FAIL;
diff --git a/dlls/mshtml/htmlwindow.c b/dlls/mshtml/htmlwindow.c
index 8a7119c5451..1343c75ba34 100644
--- a/dlls/mshtml/htmlwindow.c
+++ b/dlls/mshtml/htmlwindow.c
@@ -3926,6 +3926,9 @@ HRESULT HTMLWindow_invoke(DispatchEx *dispex, DISPID id, LCID lcid, WORD flags,
         case DISPATCH_PROPERTYPUT: {
             DISPID dispex_id;
 
+            if(This->event_target.dispex.jsdisp)
+                return S_FALSE;
+
             hres = dispex_get_dynid(&This->event_target.dispex, prop->name, TRUE, &dispex_id);
             if(FAILED(hres))
                 return hres;