WinForm lost focus to another application requires two clicks on toolstrip button

private bool handleFirstClickOnActivated = false;

/// <summary>
/// Raises the <see cref="E:System.Windows.Forms.Form.Activated" /> event.
/// Handle WinForms bug for first click during activation
/// </summary>
/// <param name="e">An <see cref="T:System.EventArgs" /> that contains the event data.</param>
protected override void OnActivated(EventArgs e)
{
    base.OnActivated(e);
    if (this.handleFirstClickOnActivated)
    {
        var cursorPosition = Cursor.Position;
        var clientPoint = this.PointToClient(cursorPosition);
        var child = this.GetChildAtPoint(clientPoint);
        while (this.handleFirstClickOnActivated && child != null)
        {
            var toolStrip = child as ToolStrip;
            if (toolStrip != null)
            {
                this.handleFirstClickOnActivated = false;
                clientPoint = toolStrip.PointToClient(cursorPosition);
                foreach (var item in toolStrip.Items)
                {
                    var toolStripItem = item as ToolStripItem;
                    if (toolStripItem != null && toolStripItem.Bounds.Contains(clientPoint))
                    {
                        var tsMenuItem = item as ToolStripMenuItem;
                        if (tsMenuItem != null)
                        {
                            tsMenuItem.ShowDropDown();
                        }
                        else
                        {
                            toolStripItem.PerformClick();
                        }
                        break;
                    }
                }
            }
            else
            {
                child = child.GetChildAtPoint(clientPoint);
            }
        }
        this.handleFirstClickOnActivated = false;
    }
}


/// <summary>
/// Handle WndProc
/// </summary>
/// <param name="m">The Windows <see cref="T:System.Windows.Forms.Message" /> to process.</param>
protected override void WndProc(ref Message m)
{
    const int WM_ACTIVATE = 0x0006;
    const int WA_CLICKACTIVE = 0x0002;
    if (m.Msg == WM_ACTIVATE && Low16(m.WParam) == WA_CLICKACTIVE)
    {
        handleFirstClickOnActivated = true;
    }
    base.WndProc(ref m);
}

private static int GetIntUnchecked(IntPtr value)
{
    return IntPtr.Size == 8 ? unchecked((int)value.ToInt64()) : value.ToInt32();
}

private static int Low16(IntPtr value)
{
    return unchecked((short)GetIntUnchecked(value));
}

private static int High16(IntPtr value)
{
    return unchecked((short)(((uint)GetIntUnchecked(value)) >> 16));
}