diff --git a/src/xinput.xml b/src/xinput.xml
index faa67ac..e3e71cb 100644
--- a/src/xinput.xml
+++ b/src/xinput.xml
@@ -385,7 +385,7 @@ authorization from the authors.
     <request name="UngrabDeviceKey" opcode="16">
         <field type="WINDOW" name="grabWindow" />
         <field type="CARD16" name="modifiers" mask="ModMask" />
-        <field type="CARD8"  name="modifier_device" />
+        <field type="CARD8"  name="modifier_device" altenum="ModifierDevice" />
         <field type="CARD8"  name="key" altenum="Grab" />
         <field type="CARD8"  name="grabbed_device" />
     </request>