Clicking and dragging on a Widget component of an actor that spawns a copy and deletes it's self can cause a crash

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.

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

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]