Wisej.Web.DataGridView.OnBindingContextChanged -- Object reference not set to an instance of an object

In 3.5.6-preview.4, during closing of a tab page.

 

17:21:32.150 [02:12344:017] ERROR  (Global)
=== [System.NullReferenceException] = [0x80004003 (-2147467261)] ============= [dk999] = [2024-04-21 17:21 JST (Sun)] ===
Object reference not set to an instance of an object.
—————————-
Source: Wisej.Framework
—————————-
at Wisej.Web.DataGridView.OnBindingContextChanged(EventArgs e)
at Wisej.Web.Control.OnParentBindingContextChanged(EventArgs e)
at System.Windows.Forms.Control.OnBindingContextChanged(EventArgs e)
at Wisej.Web.Control.OnBindingContextChanged(EventArgs e)
at Wisej.Web.Control.OnParentBindingContextChanged(EventArgs e)
at System.Windows.Forms.Control.OnBindingContextChanged(EventArgs e)
at Wisej.Web.Control.OnBindingContextChanged(EventArgs e)
at Wisej.Web.Control.AssignParent(Control parent)
at Wisej.Web.TabPage.AssignParent(Control parent)
at Wisej.Web.Control.ControlCollection.Remove(Control child)
at Wisej.Web.TabControl.ControlCollection.Remove(Control control)
at Wisej.Web.TabControl.TabPageCollection.Remove(TabPage tabPage)
at Wisej.Web.TabControl.ProcessCloseWebEvent(WisejEventArgs e)
at Wisej.Web.TabControl.OnWebEvent(WisejEventArgs e)
at Wisej.Web.Control.Wisej.Core.IWisejComponent.Event(WisejEventArgs e)
at Wisej.Web.Application.ProcessWebEvent(WisejEventArgs e)
at Wisej.Web.Application.OnWebEvent(WisejEventArgs e)
at Wisej.Web.Application.Wisej.Core.IWisejComponent.Event(WisejEventArgs e)
at Wisej.Core.ComponentManager.DispatchEvents(Session session, ICollection events)
at CallSite.Target(Closure , CallSite , ComponentManager , Session , Object )
at Wisej.Core.ResponseManager.<>c__DisplayClass30_0.<OnEvent>b__0()
at Wisej.Core.IWisejSynchronizedImplementation.Lock(IWisejSynchronized target, Action action)
at Wisej.Core.ResponseManager.OnEvent(Session session, Object message)
at CallSite.Target(Closure , CallSite , ResponseManager , Session , Object )
at Wisej.Core.ResponseManager.ProcessRequest(ServiceType service, Object message)