MainWindow{
...
AssignTO: main;
...
}
flag := win.GetWindowLong(main.Handle(), win.GWL_STYLE)
flag |= win.WS_OVERLAPPED // always on top
flag &= ^win.WS_THICKFRAME // fixed size
win.SetWindowLong(main.Handle(), win.GWL_STYLE, flag)
main.Run()