Crash when adding second position Y Animation to Widget Blueprint

On Unreal Engine 4.10.4, here is how you can replicate this crash;

  1. Create a User Interface > Widget Blueprint
  2. Drag in a button;
  3. Click “Show animation keys in curve editor”. (The crash only happens when this is active)
  4. Create an animation where on 0.0 seconds the position Y is 0 and on 0.5 seconds, the position is 150;
  5. Create a second animation.
  6. BOOM!

MachineId:EFE94E594F1154D90EDB0DADE4D1037B
EpicAccountId:1fdd523f221c45a4a0c941ab8aa09d57

Unknown exception - code 00000001 (first/second chance not available)

"Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.10\Engine\Source\Runtime\Core\Public\Containers\Array.h]

UE4Editor_Core!FDebug::AssertFailed() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\misc\outputdevice.cpp:374]
UE4Editor_Sequencer!TArray,FDefaultAllocator>::Last() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\public\containers\array.h:825]
UE4Editor_Sequencer!FSequencer::GetFocusedMovieSceneSequence() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\sequencer\private\sequencer.cpp:292]
UE4Editor_Sequencer!FSequencer::OnViewRangeChanged() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\sequencer\private\sequencer.cpp:1221]
UE4Editor_Sequencer!TBaseSPMethodDelegateInstance<0,FSequencer,0,TTypeWrapper cdecl(TRange,enum EViewRangeInterpolation,bool)>::Execute() [d:\buildfarm\buildmachine++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:282]
UE4Editor_Sequencer!TBaseSPMethodDelegateInstance<0,FSequencer,0,void cdecl(TRange,enum EViewRangeInterpolation,bool)>::ExecuteIfSafe() [d:\buildfarm\buildmachine++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:388]
UE4Editor_Sequencer!TBaseDelegate,enum EViewRangeInterpolation,bool>::ExecuteIfBound() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:482]
UE4Editor_Sequencer!TBaseFunctorDelegateInstance cdecl(float,float), >::Execute() [d:\buildfarm\buildmachine++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:1008]
UE4Editor_UnrealEd!SCurveEditor::ZoomToFitHorizontal() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.10\engine\source\editor\unrealed\private\scurveeditor.cpp:2379]
UE4Editor_UnrealEd!SCurveEditor::ZoomToFit() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.10\engine\source\editor\unrealed\private\scurveeditor.cpp:2482]
UE4Editor_Sequencer!SSequencerCurveEditor::NodeTreeSelectionChanged() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\sequencer\private\ssequencercurveeditor.cpp:181]
UE4Editor_Sequencer!TBaseSPMethodDelegateInstance<0,SSequencerCurveEditor,0,TTypeWrapper cdecl(void)>::Execute() [d:\buildfarm\buildmachine++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:282]
UE4Editor_Sequencer!TBaseSPMethodDelegateInstance<0,SSequencerCurveEditor,0,void cdecl(void)>::ExecuteIfSafe() [d:\buildfarm\buildmachine++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:387]
UE4Editor_Sequencer!TBaseMulticastDelegate::Broadcast() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:809]
UE4Editor_Sequencer!FSequencerSelection::EmptySelectedOutlinerNodes() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.10\engine\source\editor\sequencer\private\sequencerselection.cpp:155]
UE4Editor_Sequencer!FSequencer::ResetToNewRootSequence() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\sequencer\private\sequencer.cpp:302]
UE4Editor_UMGEditor!FWidgetBlueprintEditor::ChangeViewedAnimation() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\umgeditor\private\widgetblueprinteditor.cpp:594]
UE4Editor_UMGEditor!SUMGAnimationList::OnSelectionChanged() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\umgeditor\private\tabfactory\animationtabsummoner.cpp:396]
UE4Editor_UMGEditor!TBaseSPMethodDelegateInstance<0,SUMGAnimationList,0,TTypeWrapper cdecl(TSharedPtr,enum ESelectInfo::Type)>::Execute() [d:\buildfarm\buildmachine++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:282]
UE4Editor_UMGEditor!TBaseSPMethodDelegateInstance<0,SUMGAnimationList,0,void cdecl(TSharedPtr,enum ESelectInfo::Type)>::ExecuteIfSafe() [d:\buildfarm\buildmachine++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:388]
UE4Editor_UMGEditor!TBaseDelegate,enum ESelectInfo::Type>::ExecuteIfBound() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.10\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:482]
UE4Editor_UMGEditor!SListView >::Private_SignalSelectionChanged() [d:\buildfarm\buildmachine
++depot+ue4-releases+4.10\engine\source\runtime\slate\public\widgets\views\slistview.h:609]
UE4Editor_UMGEditor!STableRow >::OnMouseButtonUp() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\slate\public\widgets\views\stablerow.h:446]
UE4Editor_Slate!::operator()() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4276]
UE4Editor_Slate!FEventRouter::Route >() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:214]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4266]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4663]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4641]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\windows\windowsapplication.cpp:1416]
UE4Editor_Core!FWindowsApplication::DeferMessage() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\windows\windowsapplication.cpp:1721]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\windows\windowsapplication.cpp:719]
UE4Editor_Core!FWindowsApplication::AppWndProc() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\windows\windowsapplication.cpp:641]
user32
user32
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:884]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\launchengineloop.cpp:2391]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll

Hi SergioAlonso,

Thanks for providing concise repro steps and your callstack. I have used this information to log the following bug report: JIRA [UE-28546]. When this issue has been resolved, we will notify you with an update to this post.

-.

We are no longer able to reproduce this in UE4.11. Please test in this version of the engine and let me know if you are still experiencing this crash -thanks.

I just tested it and it works perfectly now.