diff --git a/module/doc/ui/createlib.html.php b/module/doc/ui/createlib.html.php
index c802da77b2..b343c766cb 100644
--- a/module/doc/ui/createlib.html.php
+++ b/module/doc/ui/createlib.html.php
@@ -52,7 +52,7 @@ formPanel
             set::name('execution'),
             set::items($executionPairs),
             set::placeholder($lang->doclib->tip->selectExecution),
-            set::disabled(!$project->multiple)
+            set::disabled(empty($project->multiple))
         ),
         formGroup
         (