How to get checkbox to function properly on Access 2010 report?

I’m developing a DB application via MS Access 2010. I have added an unbound, binary checkbox to a report with the purpose that a user can choose one of two record sources (queries), for two variations of the report. The checkbox Control Source property is blank and the Triple State is set to No.

However, upon opening the report, the checkbox is permanently greyed out, no matter haw many times it is clicked! Also, upon each single click on the checkbox, my_checkbox_Click() fires twice with its value toggling between Null and True! The Null value seems to be interpreted as False which might be OK if the event didn't double-fire on each single click.

How do I get my checkbox to both appear properly -- as a binary checkbox, toggling between yes and no -- and function correctly, firing _Click() only once per click? If it's a known issue with no solution, which is the best button type as a workaround?

My code:

Private Sub Report_Load()
    Debug.Print vbCrLf & "Report_Load"
    Me.my_chk.Value = False
    set_data_source
End Sub

Private Sub my_chk_Click()
    Debug.Print vbCrLf & "my_chk_Click"
    set_data_source
End Sub

Private Sub set_data_source()
    Debug.Print vbCrLf & "set_data_source"
    Debug.Print "Me.my_chk.Value", Me.my_chk.Value
    Debug.Print "Me.my_chk.ControlSource ", Me.my_chk.ControlSource
    Debug.Print "Me.my_chk.TripleState ", Me.my_chk.TripleState
    Me.RecordSource = IIf(Me.my_chk.Value, "my_yes_qry", "my_no_qry")
    Me.Requery
    Debug.Print "Me.RecordSource", Me.RecordSource
End Sub

Immediate window:

Report_Load

set_data_source
Me.my_chk.Value         False
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_no_qry

' click once on checkbox

my_chk_Click

set_data_source
Me.my_chk.Value         Null
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_no_qry

my_chk_Click

set_data_source
Me.my_chk.Value         -1 
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_yes_qry

' click once on checkbox

my_chk_Click

set_data_source
Me.my_chk.Value         Null
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_no_qry

my_chk_Click

set_data_source
Me.my_chk.Value         -1 
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_yes_qry

The only good news is that the Requery after a RecordSource changes does correctly (if all-too-briefly) affect the data.

Another thing, even though my checkbox doesn't have an AfterUpdate listed under Events, if I replace the above my_checkbox_Click() handler with

Private Sub my_chk_AfterUpdate()
    Debug.Print vbCrLf & "my_chk_AfterUpdate"
    set_data_source
End Sub

I get

Report_Load

set_data_source
Me.my_chk.Value   False
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_no_qry

' click once on checkbox

my_chk_AfterUpdate

set_data_source
Me.my_chk.Value   -1 
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_yes_qry

' click once on checkbox

my_chk_AfterUpdate

set_data_source
Me.my_chk.Value   -1 
Me.my_chk.ControlSource         
Me.my_chk.TripleState           False
Me.RecordSource             my_yes_qry

which, as you can see, doesn't work either because now, even though AfterUpdate fires once per click, the checkbox value doesn't change!

Over at http://ift.tt/1gyrfxu there was a suggestion (regarding a form, not a report) to use fancy coding

Nz(Me.my_chk = True, False)

which I tried but it had no difference in outcome.