Failed while clicking on lower "Stage file" option from context menu.

ERROR [2016-02-18 15:48:00,698] [1] [SourceTree.AppRoot] [HandleCrash] - Fatal error
System.NullReferenceException: Object reference not set to an instance of an object.
at SourceTree.ViewModel.RepoTabViewModel.ToggleStaging(IFileStatusRecord fileStatusRecord) in C:\projects\bitbucket.org\atlassian\sourcetreewin-prod\SourceTree.Api.UI.Wpf\ViewModel\RepoTabViewModel.cs:line 833
at SourceTree.ViewModel.Utils.CommandSink.ExecuteCommand(ICommand command, Object parameter, Boolean& handled) in C:\projects\bitbucket.org\atlassian\sourcetreewin-prod\SourceTree.Api.UI.Wpf\ViewModel\Utils\CommandSink.cs:line 112
at SourceTree.ViewModel.Utils.CommandSinkBinding.<set_CommandSink>b__3_1(Object s, ExecutedRoutedEventArgs e) in C:\projects\bitbucket.org\atlassian\sourcetreewin-prod\SourceTree.Api.UI.Wpf\ViewModel\Utils\CommandSinkBinding.cs:line 46
at System.Windows.Input.CommandBinding.OnExecuted(Object sender, ExecutedRoutedEventArgs e)
at System.Windows.Input.CommandManager.ExecuteCommandBinding(Object sender, ExecutedRoutedEventArgs e, CommandBinding commandBinding)
at System.Windows.Input.CommandManager.FindCommandBinding(CommandBindingCollection commandBindings, Object sender, RoutedEventArgs e, ICommand command, Boolean execute)
at System.Windows.Input.CommandManager.FindCommandBinding(Object sender, RoutedEventArgs e, ICommand command, Boolean execute)
at System.Windows.Input.CommandManager.OnExecuted(Object sender, ExecutedRoutedEventArgs e)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.Input.RoutedCommand.ExecuteImpl(Object parameter, IInputElement target, Boolean userInitiated)
at System.Windows.Input.CommandManager.TransferEvent(IInputElement newSource, ExecutedRoutedEventArgs e)
at System.Windows.Input.CommandManager.OnExecuted(Object sender, ExecutedRoutedEventArgs e)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.Input.RoutedCommand.ExecuteImpl(Object parameter, IInputElement target, Boolean userInitiated)
at MS.Internal.Commands.CommandHelpers.CriticalExecuteCommandSource(ICommandSource commandSource, Boolean userInitiated)
at System.Windows.Controls.MenuItem.InvokeClickAfterRender(Object arg)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)