By fthe way, if you want me I can send patch with my changes, but I guess Martin will provide better working code than I, and I have slightly different opinion about borders (I don't care abiut them at all).
Skickat från min Samsung-enhet
-------- Originalmeddelande -------- Från: martin rudalics <rudalics@gmx.at> Datum: 2017-01-11 09:39 (GMT+01:00) Till: Arthur Miller <arthur.miller.no1@gmail.com>, Clément Pit--Claudel <clement.pit@gmail.com> Kopia: Eli Zaretskii <eliz@gnu.org>, 25408@debbugs.gnu.org Rubrik: Re: bug#25408: Remove Decorations Around Emacs Frame (Windows OS)
> There is a slightly cosmetic issue with above function. When one switches > back on decorations, > the frame will not resize properly and minibuffer will be not visible. It's > there but just > covered by frame. Just resizing emacs framefixes it. > > Adding call to PostMessage(hwnd, WM_SIZE,0,0) in Martins function fixes it.
This is not necessary here. And it would be strange since the idea is that the outer frame size remains unchanged. Hence, any problem would manifest itself already when you remove the borders by leaving parts of the display area reserved for the frame not redrawn.
The image you posted in the message you sent just now seems to confirm that.
But I'm testing this on Windows XP and have not yet pulled the recent multi-thread Emacs changes.