Description

When a widget component is clicked and dragged upon rapidly and that widget creates a copy of it's self and destroys the previous version it can cause a crash.

Steps to Reproduce
  1. Open up a Third person project
  2. Create a New widget blue print
  3. Open the Widget blueprint
  4. Place an image widget in to the designer tab
  5. Size it to 100 by 100
  6. Set the preview size to 100 by 100
  7. Compile and save
  8. Create a new Actor blueprint
  9. Add a scene component to the blueprint
  10. Add a widget component to the blueprint
  11. Set the Widget class to the new widget blueprint that was just created
  12. Set the size of the widget component to 100 by 100
  13. Go to the event graph of the actor
  14. Create the blueprint in the attached image
  15. Compile and save
  16. Add the actor to the level
  17. Create a new player controller
  18. Go into the Class defaults of the player controller
  19. Set Show mouse cursor and Enable Click events to true
  20. Save
  21. Open the Game mode
  22. Set the player controller to the one that was just created
  23. Play in editor
  24. Click and drag rapidly on the widget component
  25. Notice that the editor will crash

Expected: The widget replaces its self and the editor does not crash
Result: The editor crashes with rapidly clicking and dragging on the widget component

Callstack

MachineId:E74C21034048BDD873CC6C9A3913CF6C
EpicAccountId:ccbf39de6f9245c0aa23f8e57cc8a566

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

Assertion failed: IsValid() [Link Removed] [Line: 658]

KERNELBASE + 37901 bytes
UE4Editor_Core!FOutputDeviceWindowsError::Serialize() + 292 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor_Core!FOutputDevice::Logf__VA() + 248 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:144]
UE4Editor_Core!FDebug::AssertFailed() + 1079 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:224]
UE4Editor_UMG!UWidgetComponent::GetHitWidgetPath() + 681 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\umg\private\components\widgetcomponent.cpp:807]
UE4Editor_UMG!FWidget3DHitTester::GetBubblePathAndVirtualCursors() + 1185 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\umg\private\components\widgetcomponent.cpp:171]
UE4Editor_SlateCore!FHittestGrid::GetWidgetPathAndDist() + 365 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\input\hittestgrid.cpp:628]
UE4Editor_SlateCore!FHittestGrid::GetBubblePath() + 362 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\input\hittestgrid.cpp:148]
UE4Editor_Slate!FSlateApplication::LocateWindowUnderMouse() + 532 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:831]
UE4Editor_Slate!FSlateApplication::UpdateToolTip() + 217 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:2640]
UE4Editor_Slate!FSlateApplication::ProcessMouseMoveEvent() + 100 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4179]
UE4Editor_Slate!FSlateApplication::OnMouseMove() + 580 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4145]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() + 2984 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsapplication.cpp:1420]
UE4Editor_Core!FWindowsApplication::DeferMessage() + 318 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsapplication.cpp:1669]
UE4Editor_Core!FWindowsApplication::ProcessMessage() + 4016 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsapplication.cpp:742]
UE4Editor_Core!FWindowsApplication::AppWndProc() + 114 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsapplication.cpp:604]
user32 + 105425 bytes
user32 + 104666 bytes
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() + 118 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:774]
UE4Editor!FEngineLoop::Tick() + 3737 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:2233]
UE4Editor!GuardedMain() + 1404 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

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Cannot Reproduce
ComponentUE - Editor - UI Systems
Affects Versions4.7.6
CreatedJun 24, 2015
ResolvedJan 5, 2017
UpdatedApr 27, 2018