Use checked handles for app dialogs

src/node_usermanual.cpp

@@ -1,6 +1,5 @@
 #include "pch.h"
 #include "log.h"
-#include "legacy_ui_overlay_services.h"
 #include "node_usermanual.h"
 #include "layout.h"
 
@@ -17,7 +16,6 @@ void NodeUserManual::init()
     SetPositioning(YGPositionTypeAbsolute);
     add_child_file("data/dialogs/usermanual.xml", "usermanual");
     btn_ok = find<NodeButton>("btn-ok");
-    pp::panopainter::bind_legacy_click_destroys_node(*btn_ok, *this);
 }
 
 kEventResult NodeUserManual::handle_event(Event* e)