Lots of work is duplicated when NonClientIslandWindow is resized and the drag bar size changes #1897

        const auto windowRect = GetWindowRect();
        const auto width = windowRect.right - windowRect.left;
        const auto height = windowRect.bottom - windowRect.top;

        const auto scale = GetCurrentDpiScale();
        const auto dpi = ::GetDpiForWindow(_window.get());

        const auto dragY = ::GetSystemMetricsForDpi(SM_CYDRAG, dpi);
        const auto dragX = ::GetSystemMetricsForDpi(SM_CXDRAG, dpi);

        // If we're maximized, we don't want to use the frame as our margins,
        // instead we want to use the margins from the maximization. If we included
        // the left&right sides of the frame in this calculation while maximized,
        // you' have a few pixels of the window border on the sides while maximized,
        // which most apps do not have.
        const auto bordersWidth = _isMaximized ?
                                      (_maximizedMargins.cxLeftWidth + _maximizedMargins.cxRightWidth) :
                                      (dragX * 2);
        const auto bordersHeight = _isMaximized ?
                                       (_maximizedMargins.cyBottomHeight + _maximizedMargins.cyTopHeight) :
                                       (dragY * 2);

        const auto windowsWidth = width - bordersWidth;
        const auto windowsHeight = height - bordersHeight;
        const auto xPos = _isMaximized ? _maximizedMargins.cxLeftWidth : dragX;
        const auto yPos = _isMaximized ? _maximizedMargins.cyTopHeight : dragY;

        const auto dragBarRect = GetDragAreaRect();
        const auto nonClientHeight = dragBarRect.bottom - dragBarRect.top;