diff --git a/examples/dockdepth1/innertabs.cpp b/examples/dockdepth1/innertabs.cpp
index 1476134..5811b7b 100644
--- a/examples/dockdepth1/innertabs.cpp
+++ b/examples/dockdepth1/innertabs.cpp
@@ -5,6 +5,8 @@
 #include <QInputDialog>
 #include <QMenu>
 
+#include <assert.h>
+
 /////////////////////////////////////
 // DockManagerWithInnerTabs
 /////////////////////////////////////