I am using the following:

Private Sub FormContainer_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
frmMain.MdiParent = Me
frmSliceInfo.MdiParent = Me
frmMain.Show()
frmMain.Dock = DockStyle.Fill
End Sub

where the FormContainer is the parent and the frmMain is the default child
form.  The child appears to go till the parent, but shows its border and
header bar.  If I click the maximize box, I get what I want.  How can I
force it to completely fill it when it loads?
Thanx,

Remove the Dock, and put this in the Load event instead:

Me.WindowState = FormWindowState.Maximized

Works just like you clicked Maximize.

2005 too smart for it's own good?
BackgroundWorker thread locking UI
Detect mouse movement from minimized application
Build a Program Now! VB2005
Help with System.Timers.Timer in a module
Edit a row
read file without locking it.
Reading text files
"File is being used by another process" - error
Form & Designer File Becoming Separated