c# an object on upper level cannot be added to an object
private void frmInitialEntryBooks_Load(object sender, EventArgs e)
{
frmSujbect objForm = new frmSujbect();
objForm.TopLevel = false;
pnl.Controls.Add(objForm);
objForm.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
objForm.Dock = DockStyle.Fill;
objForm.Show();
}