WPF - destroy page after unloaded has run - wpf

Question

In a WPF app we have the need to sometimes create a new tab that contains a Page inside a Frame..
Once the page has been opened (initialised once) it still seems to stay in navigation history and attempts to load data that may not be relevant at the time.
I have tried a myriad of methods including NavigationService.RemoveBackEntry, but it still persists :-(
This is an example of how the tab/page are opened
Private Sub CashFlow_Edit(sender As Object, e As RoutedEventArgs)
Try
Dim DGV As DGVx = ReportsCashFlow_Grid.FindName("CashFlow_DGV")
e.Handled = True
IsNewRecord = False
If DGV.SelectedItems.Count = 1 Then
Dim row As System.Data.DataRowView = DGV.SelectedItems(0)
Form_ID = row("ID")
Dim vName As String = row("Name")
Dim vTab As STC_Tabx = Application.Current.MainWindow.FindName(TabName)
Dim TabControl As STCx = Application.Current.MainWindow.FindName("AccountingReports_TabControl")
If Not vTab Is Nothing Then
vTab.Close()
End If
Dim MCFrame As New Frame
Dim MCTab As New STC_Tabx
With MCTab
.Name = TabName
.Header = " " & vName & " "
.ImageSource = ReturnImageAsString("Edit.png", 16)
.CloseButtonVisibility = DevComponents.WpfEditors.eTabCloseButtonVisibility.Visible
.TabToolTip = "View or edit the " & vName & " template"
.Content = MCFrame
End With
RemoveHandler MCTab.Closing, AddressOf TabControl_TabClosing
AddHandler MCTab.Closing, AddressOf TabControl_TabClosing
Dim vGrid As Grid = Application.Current.MainWindow.FindName("MainGrid_Accounting")
RegisterControl(vGrid, MCTab)
TabControl.Items.Add(MCTab)
Dim MCPage As New ReportCashFlow_Page
MCFrame.NavigationService.Navigate(MCPage)
LoadedTabs(TabName)
MCTab.IsSelected = True
End If
Catch ex As Exception
EmailError(ex)
End Try
End Sub

Answer 1

To remove all the back entries do something like:
while(NavigationService.CanGoBack)
{
NavigationService.RemoveBackEntry();
}

Answer 2

It's not the clean bit of code I would like, but it works - create a global Boolean - when the sub that opens the tab/page is called it's set to true and the loading event will only run the loading code if this is true - it's set to false at the end.
Private Sub ReportCashFlow_Page_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
Try
If IsNewTab = False Then
Exit Sub
End If
'Run all the loading code here
Catch ex As Exception
EmailError(ex)
Finally
IsNewTab = False
Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, CType(Sub() CashFlow_LoadBudget(), SendOrPostCallback), Nothing)
Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, CType(Sub() ToggleReserve(), SendOrPostCallback), Nothing)
End Try
End Sub