diff --git a/reactos/lib/aclui/aclui.xml b/reactos/lib/aclui/aclui.xml
index c0679abac91..8d260222f73 100644
--- a/reactos/lib/aclui/aclui.xml
+++ b/reactos/lib/aclui/aclui.xml
@@ -7,6 +7,7 @@
 	<define name="_WIN32_IE">0x0500</define>
 	<define name="_WIN32_WINNT">0x0600</define>
 	<define name="WINVER">0x0600</define>
+	<define name="SUPPORT_UXTHEME" />
 	<library>ntdll</library>
 	<library>kernel32</library>
 	<library>user32</library>