diff --git a/src/frontends/controllers/ControlSpellchecker.h b/src/frontends/controllers/ControlSpellchecker.h
index 70c205bd4e..75b58b51ee 100644
--- a/src/frontends/controllers/ControlSpellchecker.h
+++ b/src/frontends/controllers/ControlSpellchecker.h
@@ -20,6 +20,7 @@
 #endif
 
 #include "ControlDialog_impl.h"
+#include "LString.h"
 
 class SpellBase;