# Runtime error **URL:** \ **Category:** General\ **Created:** [September 22, 2015, 6:58pm UTC](https://forums.fusetools.com/t/runtime-error/4724 "2015-09-22T18:58:08Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Daniel\_Hellkert](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/daniel_hellkert/32/224_2.png) [@Daniel\_Hellkert](https://forums.fusetools.com/u/Daniel_Hellkert)\ **Post date:** [September 22, 2015, 6:58pm UTC](https://forums.fusetools.com/t/runtime-error/4724/1 "2015-09-22T18:58:08Z")
The app crash in runtime with the following stacktrace, do you know why? \_wapi\_handle\_unref\_full: Attempting to unref unused handle 0x41a # Oops! Object reference not set to an instance of an object at Outracks.Simulator.Runtime.CompiledTypeReflection.SetPropertyValue (System.Object obj, Outracks.Simulator.Bytecode.TypeMemberName propertyName, System.Object value) [0x00000] in :0 at Outracks.Fuse.Preview.PreviewLocally+c **AnonStorey3.\<\>m** 2 (System.Object a, System.String b, System.Object c) [0x00000] in :0 at Outracks.Simulator.Reflection.DelegateReflection.Outracks.Simulator.Runtime.IReflection.SetPropertyValue (System.Object instance, Outracks.Simulator.Bytecode.TypeMemberName propertyName, System.Object value) [0x00000] in :0 at Outracks.Simulator.Runtime.ScopeClosure.Evaluate (Outracks.Simulator.Bytecode.WriteProperty p) [0x00000] in :0 at Outracks.Simulator.Bytecode.Expression.Match[Object] (System.Func`2 a1, System.Func`2 a2, System.Func`2 a3, System.Func`2 a4, System.Func`2 a5, System.Func`2 a6, System.Func`2 a7, System.Func`2 a8, System.Func`2 a9, System.Func`2 a10, System.Func`2 a11, System.Func`2 a12, System.Func`2 a13, System.Func`2 a15, System.Func`2 a16) [0x00000] in :0 at Outracks.Simulator.Runtime.ScopeClosure.Evaluate (Outracks.Simulator.Bytecode.Expression expression) [0x00000] in :0 at Outracks.Simulator.Runtime.ScopeClosure.Execute (IEnumerable`1 statements) [0x00000] in :0 at Outracks.Simulator.Runtime.ScopeClosure.Execute (Outracks.Simulator.Bytecode.Lambda lambda, Outracks.Simulator.Runtime.ScopeClosure& bodyClosure, System.Object[] arguments) [0x00000] in :0 at Outracks.Simulator.Runtime.ScopeClosure.Execute (Outracks.Simulator.Bytecode.Lambda lambda, System.Object[] arguments) [0x00000] in :0 at Outracks.Simulator.Runtime.LambdaClosure.Func (System.Object a1, System.Object a2) [0x00000] in :0 at Outracks.Simulator.Runtime.LambdaClosure.Action (System.Object a1, System.Object a2) [0x00000] in :0 at Outracks.Simulator.Runtime.UxProperty`1[System.Int32].OnSet (Int32 value, System.Object origin) [0x00000] in :0 at Uno.UX.Property`1[System.Int32].SetRestState (Int32 value, System.Object origin) [0x00000] in :0 at Fuse.Reactive.DataBinding`1[System.Int32].SetValue (Int32 value) [0x00000] in :0 at Fuse.Reactive.Marshal.ToType[Int32] (System.Object o, System.Action`1 callback) [0x00000] in :0 at Fuse.Reactive.DataBinding`1[System.Int32].PushValue (System.Object newValue) [0x00000] in :0 at Fuse.Reactive.DataBinding`1[System.Int32].NewValue (System.Object value) [0x00000] in :0 at Fuse.Reactive.PathSubscription.HandlePath (System.Object dc, System.String path) [0x00000] in :0 at Fuse.Reactive.PathSubscription.HandleNewDataContext (System.Object val) [0x00000] in :0 at Fuse.Reactive.PathSubscription.HandleObjectCallback (System.Object val) [0x00000] in :0 at Fuse.Reactive.TellObject.Run () [0x00000] in :0 at Fuse.Reactive.ThreadWorker.Dispatch (TaskPriority priority, System.Action action) [0x00000] in :0 at Fuse.Reactive.AsyncObject.Tell (System.String key, Fuse.Reactive.Dispatcher thread, System.Action`1 callback) [0x00000] in :0 at Fuse.Reactive.PathSubscription.HandleObject (IAsyncObject obj) [0x00000] in :0 at Fuse.Reactive.PathSubscription.HandlePath (System.Object dc, System.String path) [0x00000] in :0 at Fuse.Reactive.PathSubscription..ctor (Fuse.Reactive.Binding b, System.Object dc, System.String path) [0x00000] in :0 at Fuse.Reactive.Binding.BindToPath (System.String path, System.Object dc) [0x00000] in :0 at Fuse.Reactive.Binding.OnDataContextChanged (System.Object sender, Fuse.DataContextChangedArgs args) [0x00000] in :0 at Fuse.Reactive.Binding.OnRooted (Fuse.Node n) [0x00000] in :0 at Fuse.Reactive.DataBinding`1[System.Int32].OnRooted (Fuse.Node n) [0x00000] in :0 at Fuse.Behavior.Rooted (Fuse.Node e) [0x00000] in :0 at Fuse.Node.RootBehaviors () [0x00000] in :0 at Fuse.Node.MarkRooted () [0x00000] in :0 at Fuse.Node.OnAdded (Fuse.Node parent) [0x00000] in :0 at Fuse.Controls.Internal.ChildCollection.AddChild (Fuse.Node child) [0x00000] in :0 at Fuse.Controls.Internal.ChildCollection.Add (Fuse.Node item) [0x00000] in :0 at Fuse.Reactive.Each.AddNew (System.Object dataContext) [0x00000] in :0 at Fuse.Reactive.Each.ReplaceAll (System.Object[] dcs) [0x00000] in :0 at Fuse.Reactive.Dispatcher+ArgDispatch`1[System.Object[]].Run () [0x00000] in :0 at Fuse.Reactive.Dispatcher+UIThreadDispatcher.Run () [0x00000] in :0 at Fuse.UpdateListener.Invoke () [0x00000] in :0 at Fuse.UpdateManager.Update (Fuse.Stage stage) [0x00000] in :0 at Fuse.UpdateManager.Update () [0x00000] in :0 at Fuse.App.Update () [0x00000] in :0 ---
**Author:** ![Anders\_Lassen](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/anders_lassen/32/522_2.png) [@Anders\_Lassen](https://forums.fusetools.com/u/Anders_Lassen)\ **Post date:** [September 22, 2015, 7:11pm UTC](https://forums.fusetools.com/t/runtime-error/4724/2 "2015-09-22T19:11:53Z")
Thanks for reporting, we’ll look into it shortly. If you can provide a test case to reproduce this, that would be awesome. ---
**Author:** ![Daniel\_Hellkert](https://yyz1.discourse-cdn.com/flex035/user_avatar/forums.fusetools.com/daniel_hellkert/32/224_2.png) [@Daniel\_Hellkert](https://forums.fusetools.com/u/Daniel_Hellkert)\ **Post date:** [September 22, 2015, 7:53pm UTC](https://forums.fusetools.com/t/runtime-error/4724/3 "2015-09-22T19:53:49Z")
The row/column-binding makes it crash, the binding worked before but not in 0.5.7 Here is the UX-code: ```auto ... ```