Hello Overloaded_Name,
Delete the OnMouseDown method and change tabMainTabCtrl_SelectedIndexChanged method as below
private void tabMainTabCtrl_SelectedIndexChanged(object sender, EventArgs e)
{
if ( tabMainTabCtrl.SelectedIndex != 0)
{
if ( !IsUserAuthenticated )
{
MessageBox.Show("You are not authenticated user");
tabMainTabCtrl.SelectedIndex = 0;
}
}
}
I thing this help you.