How to merge mdi parent child toolstrip?

How to merge mdi parent child toolstrip?

How can i find toolstrip1 control on child form. This does not work:
private void EUF_MdiChildActivate(object sender, EventArgs e)
{
ToolStripManager.Merge(this.ActiveMdiChild.Controls("toolStrip1"),
toolStrip1);
}
I get an error :
Error 1
Non-invocable member 'System.Windows.Forms.Control.Controls' cannot
be used like a method.