diff --git a/src/Undo.cpp b/src/Undo.cpp
index c0cf56925e..693008268a 100644
--- a/src/Undo.cpp
+++ b/src/Undo.cpp
@@ -612,7 +612,9 @@ void Undo::endUndoGroup(CursorData const & cur_after)
 
 bool Undo::activeUndoGroup() const
 {
-	return d->group_level_ > 0 && d->undostack_.top().group_id == d->group_id_;
+	return d->group_level_ > 0
+		&& !d->undostack_.empty()
+		&& d->undostack_.top().group_id == d->group_id_;
 }