If you have an MDI form with controls anchored to bottom-left, and if the form is shown the following way:

Form form = new ChildForm()
form.MdiParent = this;
form.Show();

private void ChildForm_Load(object sender, EventArgs e)
{
         this.ThemeName = "Office2007Black";
}

the anchored controls will be misplaced.

WORKAROUND:

either set the parent after show:
Form form = new ChildForm()
form.Show();
form.MdiParent = this;

or do not use the Load event to apply theme - use the constructor or the Shown event:

public ChildForm()
{ 
         InitializeComponent();
         this.ThemeName = "Office2007Black";
}