I have a userform set up so that when the "Enter" button is pressed, if any text box is empty, it will set focus and change its background colour to highlight the missing entry.

This works fine as per my excerpt from my code below. But I was wondering if it would be possible to in essence remove the focus event once someone starts to type something in the box that previously had nothing in it?

Private Sub EnterBut_Click()

    If cbThreat.ListIndex < 1 Then
        MsgBox "Select threat level!", vbExclamation + vbOKOnly, "Triage Hub"
        cbThreat.SetFocus
        cbThreat.BackColor = RGB(102, 255, 255)
        GoTo lbl_Exit
    End If
    If cbHarm.ListIndex < 1 Then
        MsgBox "Select harm level!", vbExclamation + vbOKOnly, "Triage Hub"
        cbHarm.SetFocus
        cbHarm.BackColor = RGB(102, 255, 255)
        GoTo lbl_Exit
    End If
    If cbOpportunity.ListIndex < 1 Then
        MsgBox "Select opportunity level!", vbExclamation + vbOKOnly, "Triage Hub"
        cbOpportunity.SetFocus
        cbOpportunity.BackColor = RGB(102, 255, 255)
        GoTo lbl_Exit
    End If
    If cbRisk.ListIndex < 1 Then
        MsgBox "Select risk level!", vbExclamation + vbOKOnly, "Triage Hub"
        cbRisk.SetFocus
        cbRisk.BackColor = RGB(102, 255, 255)
        GoTo lbl_Exit
    End If
    If cbDepartment.ListIndex < 1 Then
        MsgBox "Select department to follow up!", vbExclamation + vbOKOnly, "Triage Hub"
        cbDepartment.SetFocus
        cbDepartment.BackColor = RGB(102, 255, 255)
        GoTo lbl_Exit
    End If
    If txtRationale.Text = vbNullString Then
        MsgBox "Enter rationale!", vbExclamation + vbOKOnly, "Triage Hub"
        txtRationale.SetFocus
        txtRationale.BackColor = RGB(255, 255, 204)
        GoTo lbl_Exit
    End If
    Tag = 1
    Hide
lbl_Exit:
    Exit Sub
End Sub