Use IWYU.

examples/dom/package_manager.cpp

@@ -4,9 +4,16 @@
 #include <ftxui/screen/string.hpp>
 #include <iostream>
 #include <list>
+#include <memory>
+#include <string>
 #include <thread>
+#include <utility>
 #include <vector>
 
+#include "ftxui/dom/node.hpp"
+#include "ftxui/screen/box.hpp"
+#include "ftxui/screen/color.hpp"
+
 /// @example examples/dom/package_manage.cpp
 
 int main(int argc, const char* argv[]) {