[c#] Changing the cursor in WPF sometimes works, sometimes doesn't

You can use a data trigger (with a view model) on the button to enable a wait cursor.

<Button x:Name="NextButton"
        Content="Go"
        Command="{Binding GoCommand }">
    <Button.Style>
         <Style TargetType="{x:Type Button}">
             <Setter Property="Cursor" Value="Arrow"/>
             <Style.Triggers>
                 <DataTrigger Binding="{Binding Path=IsWorking}" Value="True">
                     <Setter Property="Cursor" Value="Wait"/>
                 </DataTrigger>
             </Style.Triggers>
         </Style>
    </Button.Style>
</Button>

Here is the code from the view-model:

public class MainViewModel : ViewModelBase
{
   // most code removed for this example

   public MainViewModel()
   {
      GoCommand = new DelegateCommand<object>(OnGoCommand, CanGoCommand);
   }

   // flag used by data binding trigger
   private bool _isWorking = false;
   public bool IsWorking
   {
      get { return _isWorking; }
      set
      {
         _isWorking = value;
         OnPropertyChanged("IsWorking");
      }
   }

   // button click event gets processed here
   public ICommand GoCommand { get; private set; }
   private void OnGoCommand(object obj)
   {
      if ( _selectedCustomer != null )
      {
         // wait cursor ON
         IsWorking = true;
         _ds = OrdersManager.LoadToDataSet(_selectedCustomer.ID);
         OnPropertyChanged("GridData");

         // wait cursor off
         IsWorking = false;
      }
   }
}