Datagrid Inside MdiChildren NOT Applying Custom Format?

I have a datagridview (windows forms) that is inside an mdiChild form. The custom format is given by a "for" instance, something like this:

For row As Integer = 0 To .Rows.Count - 1
If .Rows(row).Cells("someNumber").Value = 0 Then
.Rows(row).DefaultCellStyle.BackColor = Color.DarkSeaGreen
End If
Next

So, for every row in the grid that you find, if ther value in the "somenumber" =0 paint the whole row green. Problem is, if I put the form OUTSIDE of the MDIParent - just put frmMyform.show() in my btn that calls the form-, the grid WILL apply the format; If I call it like frmMyform.mdiparent = frmMdi, then frmMyform.show, the grid WILL NOT apply the format.