اینو تست کن
       private bool altPressed;
private void ContextMenuStrip1_Closing(object? sender, ToolStripDropDownClosingEventArgs e)
{
if (e.CloseReason == ToolStripDropDownCloseReason.Keyboard && altPressed)
{
e.Cancel = true;
altPressed = false;
}
}

private void ContextMenuStrip1_PreviewKeyDown(object? sender, PreviewKeyDownEventArgs e)
{
if (e.Alt)
{
altPressed = true;
}
else
{
altPressed = false;
}
}

کد مشخصه، خودتون تبدیل کنید به vb