Combo Box on VB form locks up application

Here's the issue summary:

Developing in Visual Studio 2012 Pro using a VB.net form
SQL Server 2005 Enterprise backend.

I have a combobox (ddlContractorName) that is databound to a Contractor table.  Its display member returns a string (Fullname), and the selected value returns a  datetime associated with the Fullname for the record.  This sits in a VB form inside a tab container.  Once I click on the combobox it locks up my form.  I can’t exit out, I can’t select any other controls via mouse or keyboard.  I have to stop the program debugger to close it.  This only happens if I populate the Selected Value portion of the combobox.  If I set selected value to none, the form works perfectly.  Only problem is that I need the value for calculations and logic.

I thought this might be caused from the datetime datatype not playing nicely, but it does the same thing when I use a string value for the selected value.

What the heck is causing this?

Here’s the relevant form source code:

*********************************************************************

Public Class frmHome

    Private Sub FrmHome_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        'TODO: This line of code loads data into the 'Contractor_TrackingDataSet1.SignInOut' table. You can move, or remove it, as needed.
        Me.SignInOutTableAdapter.Fill(Me.Contractor_TrackingDataSet.SignInOut)
        lblHalt.Visible = False
        lblSignInComplete.Visible = False
        lblSignOutComplete.Visible = False
        btnOKClear.Visible = False


        'TODO: This line of code loads data into the 'Contractor_TrackingDataSet.SignInOut' table. You can move, or remove it, as needed.
        Me.SignInOutTableAdapter.Fill(Me.Contractor_TrackingDataSet.SignInOut)
        'TODO: This line of code loads data into the 'Contractor_TrackingDataSet.Company' table. You can move, or remove it, as needed.
        Me.CompanyTableAdapter.Fill(Me.Contractor_TrackingDataSet.Company)
        'TODO: This line of code loads data into the 'Contractor_TrackingDataSet.Person' table. You can move, or remove it, as needed.
        Me.PersonTableAdapter.Fill(Me.Contractor_TrackingDataSet.Person)
        'TODO: This line of code loads data into the 'Contractor_TrackingDataSet.Person' table. You can move, or remove it, as needed.

    End Sub

    Private Sub ddlContractorName_SelectedIndexChanged(sender As Object, e As EventArgs)

    End Sub

End Class
*********************************************************************


Thanks!