Thank you Naomi
this code seems to cut the native form.titlebar (form.titlebar=0) and replace it by another as container for ex.
i cannot access to the author code.
thats dont solves my problem.Its a subclassing of the native form.titlebar.
i made some works on it(for ex. at
http://yousfi.over-blog.com/2015/02/subclassing-the-form-titlebar-other-stuffs.html)

my project is to draw a cliquable button directly on the native form.titlebar or any window (as the link i pointed above).
Maybe this can be a start in http://www.news2news.com/vfp/index.php?example=238
to continue...