diff --git a/src/util/dicontheme.cpp b/src/util/dicontheme.cpp
index d0d7608..dcff2f3 100644
--- a/src/util/dicontheme.cpp
+++ b/src/util/dicontheme.cpp
@@ -126,12 +126,12 @@ bool DIconTheme::isBuiltinIcon(const QIcon &icon)
 
 bool DIconTheme::isXdgIcon(const QIcon &icon)
 {
-#ifdef DTK_DISABLE_LIBXDG
-    return false;
-#else
     if (icon.isNull())
         return false;
 
+#ifdef DTK_DISABLE_LIBXDG
+    return false;
+#else
     QIconEngine *engine = const_cast<QIcon &>(icon).data_ptr()->engine;
     if (auto proxyEngine = dynamic_cast<DIconProxyEngine *>(engine))
         return !proxyEngine->proxyKey().compare("XdgIconProxyEngine");