Sizing Textbox with form size ? [Resolved]

[BeholderOf]

I have a textbox and when i run my code it runs but not exact, the width is like 2 - 4 units off unless i subtract it manaully in code. Is there another method that is exact ?

heres my current code

Protected Overrides Sub OnResize(ByVal e As System.EventArgs)
        rt.Width = Me.Width 
        rt.Height = Me.Height
 
    End Sub

just a note:
I just started .net recently so im still learning.