ComboBox within RadGridView's Header Binding is Breaking After switching tabs

I have several Telerik RadGridViews within a TabControl.

Each of these RadGridViews has a column with CheckBoxes in. The header for this column is a CheckBox. When the user clicks the CheckBox in the header, CheckBoxes within the column are checked or unchecked accordingly.

The checking/unchecking of the CheckBoxes works for the RadGridView in the tab that is, by default, selected.

The checking/unchecking does not work in any of the RadGridViews that are in tabs that were not selected by default. When you return to the tab that selected by default, it still works.

I took a copy of the CheckBox that is in the header and placed it above the RadGridView and it works fine after switching tabs... If you check/uncheck this CheckBox it will check/uncheck all of the CheckBoxes in the Grid...but the CheckBox in the Header doesn't work.

It's almost as if the Binding for the CheckBox in the header of the Grid not applied if the Grid is not visible when the page loads....

I was wondering if anyone knows how to get around this problem.

<TablControl>
  <TabItem Header="Items">
    <telerik:RadGridView x:Name="GridA" AutoGenerateColumns="False" ItemsSource="{Binding MyItems}">
        <telerik:RadGridView.Columns>
            <telerik:GridViewBoundColumnBase>
                <telerik:GridViewBoundColumnBase.Header>
                    <CheckBox IsChecked="{Binding ElementName=TheElementBoundToTheViewModel, Path=DataContext.SelectAllMyItems, Mode=TwoWay}" />
                </telerik:GridViewBoundColumnBase.Header>
                <telerik:GridViewBoundColumnBase.CellTemplate>
                    <DataTemplate>
                        <CheckBox IsChecked="{Binding IsSelected}"></CheckBox>
                    </DataTemplate>

                </telerik:GridViewBoundColumnBase.CellTemplate>
            </telerik:GridViewBoundColumnBase>
    <!-- ...... other stuff  ..... -->

        </telerik:RadGridView.Columns>
    </telerik:RadGridView>
  </TabItem>
  <TabItem Header="ItemsB">
   <telerik:RadGridView x:Name="GridB" AutoGenerateColumns="False" ItemsSource="{Binding MyItemsB}">
        <telerik:RadGridView.Columns>
            <telerik:GridViewBoundColumnBase>
                <telerik:GridViewBoundColumnBase.Header>
                    <CheckBox IsChecked="{Binding ElementName=TheElementBoundToTheViewModel, Path=DataContext.SelectAllMyItems, Mode=TwoWay}" />
                </telerik:GridViewBoundColumnBase.Header>
                <telerik:GridViewBoundColumnBase.CellTemplate>
                    <DataTemplate>
                        <CheckBox IsChecked="{Binding IsSelected}"></CheckBox>
                    </DataTemplate>

                </telerik:GridViewBoundColumnBase.CellTemplate>
            </telerik:GridViewBoundColumnBase>
    <!-- ...... other stuff  ..... -->

        </telerik:RadGridView.Columns>
    </telerik:RadGridView>
  </TabItem>
</TabControl>

This is my ViewModel:

Public Class MyItemsVM
  Inherits ViewModelBase

  Private _selectAllMyItems As Boolean    
  Public Property MyItems As ObservableCollection(Of MyItemSelectionVM)
  Public Property SelectAllMyItems As Boolean
    Get
      Return _selectAllMyItems 
    End Get
    Set(ByVal value As Boolean)
        _selectAllMyItems = value
        For Each ivm In MyItems 
            ivm.IsSelected = _selectAllMyItems
        Next
        MyBase.RaisePropertyChangedEvent(Me, SelectAllMyItemsChanged)
      End Set
  End Property



  Private _selectAllMyItemsB As Boolean
  Public Property MyItemsB As ObservableCollection(Of MyItemSel开发者_高级运维ectionVM)
  Public Property SelectAllMyItemsB As Boolean
    Get
      Return _selectAllMyItemsB
    End Get
    Set(ByVal value As Boolean)
        _selectAllMyItemsB = value
        For Each ivm In MyItemsB 
            ivm.IsSelected = _selectAllMyItemsB
        Next
        MyBase.RaisePropertyChangedEvent(Me, SelectAllMyItemsBChanged)
      End Set
  End Property




  Public Sub New(ByVal items As MyItemList,ByVal itemsB As MyItemList)

     MyItems = New ObservableCollection(Of MyItemSelectionVM)
     For Each item In items
       MyItems.Add(New MyItemSelectionVM(item))
     Next

     MyItemsB = New ObservableCollection(Of MyItemSelectionVM)
     For Each item In itemsB
       MyItemsB.Add(New MyItemSelectionVM(item))
     Next

  End Sub

End Class



Public Class MyItemSelectionVM
    Implements INotifyPropertyChanged
    Public Event PropertyChanged(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged

    Private _isSelected As Boolean
    Private _item As MyItem

    Public Property MyItem As MyItem
        Get
            Return _item 
        End Get
        Set(ByVal value As MyItem)
            _item = value
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("MyItem"))
        End Set
    End Property

    Public Property IsSelected As Boolean
        Get
            Return _isSelected
        End Get
        Set(ByVal value As Boolean)
            _isSelected = value
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs("IsSelected"))
        End Set
    End Property

    Public Sub New(ByVal theItem As MyItem)
        _item = theItem
    End Sub
End Class

Thanks for your help

-Frinny

I solved the problem by creating a Static Resource for the View Model. Binding to the Static Resource instead of an element's DataContext fixed the problem.