How can I remove non-client area of a window (border, title), which belongs to another process (separate application)? I have only HWND of that window, and cutting its DC using SetLayeredWindowAttributes() with LWA_COLORKEY, to get some specific shape, but all non-client area remains as an ugly frame. So I need to remove it somehow.
Note: the window is created by existing application, and I can’t change its code