Change Font Size in ListView

I'm trying to change the font size of a listview in details view.

Here's an excerpt of the code I think is relevant to my problem.

Code:

---

Dim Item1 As New ListViewItem(Values(0))
Item1.UseItemStyleForSubItems = False
Item1.SubItems.Add(Values(12)).ForeColor = Color.Green
Item1.SubItems(12).Font = New Font(Item1.SubItems(12).Font, FontStyle.Bold)
ListView1.Items.Add(Item1)

---

Then in another procedure

Code:

---

ListView1.Font = New Font(ListView1.Font.FontFamily, 12, ListView1.Font.Style)

---

The result is that the column headings and every item and subitem in the listview changes to font size 12 except the subitems that were bold. The subitems that are bold do not change.

Does anyone know why?