diff --git a/src/modes/classicmode/editor/selectionmanager.h b/src/modes/classicmode/editor/selectionmanager.h
index 4be6c27..1b604dd 100644
--- a/src/modes/classicmode/editor/selectionmanager.h
+++ b/src/modes/classicmode/editor/selectionmanager.h
@@ -2,6 +2,7 @@
 
 #include <vector>
 #include <algorithm>
+#include <functional>
 
 template <class T>
 class SelectionManager