Name of MdiChild form shows up in MdiParent form's Text property when going to full screen mode C#

Question

I have a peculiar problem with my C# WinForms app (VS 2013). I have an MdiParent form that creates an MdiChild form, but it shows the name of the MdiChild form in its Text property whenever I open a file and put the MdiParent form in full screen mode. Here is the code for entering full screen mode:

    private void tsbtnFullScreen_Click(object sender, EventArgs e)
    {
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
        this.WindowState = FormWindowState.Maximized;
        this.BackColor = SystemColors.ActiveCaptionText;
        tsToolStrip.Visible = ssStatusStrip.Visible = false;
    }

Instead of seeing this in the MdiParent form's Text property: "My Trivia Game - Trivia Player v1.0"

I see this: "My Trivia Game - Trivia Player v1.0 - [frmGame]"

I tried this after opening a file and creating a new MdiChild form(frmGame):

this.Text = clsGameInfo.strGameTitle + " - " + "Trivia Player v1.0";

And I tried this:

this.Text.Replace (" - [frmGame]", "");

The MdiParent form(this) still reads "My Trivia Game - Trivia Player v1.0 - [frmGame]".

How can I get rid of or prevent " - [frmGame]" from showing up in the MdiParent form's Text property?