c# WinForms opening the Colour Dialog in child form

Question

Hi I try to open Color Dialog from my child form (the form opened by my main form).

    private void terminalScreenPanel_MouseDoubleClick(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            TextColourDialog.ShowDialog();
        }
    }

My user control is loosing the focus, but dialog does not open. It opens when I press the Alt key. I use ColorDialogs in the pareny form without any issues.