Using SetForegroundWindow to focus on a window

Question

        var hwnd = GetWindowHandle(); //Custom function that returns the target window's handle
        var currentThreadId = GetCurrentThreadId();
        uint pid;
        var targetThreadId = GetWindowThreadProcessId(hwnd, out pid);
        if (targetThreadId == IntPtr.Zero) return;
        if (targetThreadId != currentThreadId)
        {
            AttachThreadInput(currentThreadId, targetThreadId, true);
        }
        SetForegroundWindow(hwnd);
        if (currentThreadId != targetThreadId)
        {
            AttachThreadInput(currentThreadId, targetThreadId, false);
        }

I have used the above code to put focus to another window, using the Handle of the targeted window. The above code is placed inside a method which is called when a shortcut key is pressed. The issue that I am facing is that for the first time focus is getting stuck at the window, i.e., the focus is not shifting to other controls in the window (on tab press). So I have to bring the focus inside the window, using mouse. On pressing the shortcut for the 2nd time, the focus is not getting stuck anymore, its moving correctly on tab press. Also please note that I have tried using SetFocus, but I am getting the same issue.

Please suggest of there is anything wrong with the code, or if I can use any alternate method to achieve the same behavior. Thanks.