Forms :: Locking Main Form Controls Causes Data In Subform To Disappear?

So I am creating a Complaint Tracking Database with Access 2013. In my 'complaint entry form' I have added to ability to "Open" and "Close" the complaint. While the complaint is open the user is able to enter/edit data in the complaint (new or old). When the complaint is "Closed" (done so with a button on the form that prompts the user to enter a date of their choice) the user should not be able to enter/edit data in the given complaint. In my original thinking, I placed checks on various events (on load, after update, on click) that checked to see if the current complaint had a date in the "Close date" field.

If the close date field was null then that meant that the complaint was open and the the controls would NOT be locked. If the close date field was NOT null (i.e. a date was present) then the complaint was closed and the main form fields were locked but the data was still viewable and unless they "re-opened" the complaint they could not change the data.

Now, in the complaint entry form, I have a subform that acts as a action tracker that is used by the user to keep track of the actions taken on the complaint (i.e. they requested documentation from such and such on this date..etc). My problem through all of this is upon closing the complaint and locking the main form controls, my subforms data just vanishes! At first I figured the problem might be with the linking of master and child fields, so I made sure that I left the ID in the main form unlocked when I loop through my controls during the locking process. This did not solve my problem. Code below:

Private Sub Form_Load()
Dim ctl As Control
If Not IsNull(Me.close_date) Then
Me.FormHeader.Visible = True
Me.btnClosed.Enabled = False
Me.btnOpen.Enabled = True
For Each ctl In Me.Controls

[Code] .....