Crash when editing gameplay tag query in a structure

When I try to edit Gameplay tag query in a blueprint structure the editor crashes.

Regression:
No. This issue affects versions: 4.15, 4.14.3, 4.13.2 (Binary Versions)

1. Create a new empty project (No Starter Content & Specific Template needed)
2. Create a structure
3. add a gameplay tag query variable
4. Click the edit button
   Results: Editor Crashes
   Expected: The Variable can be edited

UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:349]
UE4Editor_GameplayTagsEditor!SGameplayTagQueryWidget::Construct() [d:\build\++ue4+release-4.15+compile\sync\engine\plugins\editor\gameplaytagseditor\source\gameplaytagseditor\private\sgameplaytagquerywidget.cpp:36]
UE4Editor_GameplayTagsEditor!TDecl<SGameplayTagQueryWidget,RequiredArgs::T1RequiredArgs<TArray<SGameplayTagQueryWidget::FEditableGameplayTagQueryDatum,FDefaultAllocator> & __ptr64> >::operator<<=() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\slatecore\public\widgets\declarativesyntaxsupport.h:1087]
UE4Editor_GameplayTagsEditor!FGameplayTagQueryCustomization::OnEditButtonClicked() [d:\build\++ue4+release-4.15+compile\sync\engine\plugins\editor\gameplaytagseditor\source\gameplaytagseditor\private\gameplaytagquerycustomization.cpp:179]
UE4Editor_GameplayTagsEditor!TMemberFunctionCaller<FGameplayTagQueryCustomization,FReply (__cdecl FGameplayTagQueryCustomization::*)(void) __ptr64>::operator()<>() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\public\delegates\delegateinstanceinterface.h:165]
UE4Editor_GameplayTagsEditor!TTupleImpl<TIntegerSequence<unsigned int> >::ApplyAfter<TMemberFunctionCaller<FGameplayTagQueryCustomization,FReply (__cdecl FGameplayTagQueryCustomization::*)(void) __ptr64> >() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\public\delegates\tuple.h:134]
UE4Editor_GameplayTagsEditor!TBaseSPMethodDelegateInstance<0,FGameplayTagQueryCustomization,0,FReply __cdecl(void)>::Execute() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:327]
UE4Editor_Slate!TBaseDelegate<FReply>::Execute() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl.inl:537]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:278]
UE4Editor_Slate!<lambda_8d0e9a1da76abd0a756a3a9d775f5ed1>::operator()() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5075]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_8d0e9a1da76abd0a756a3a9d775f5ed1> >() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:238]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5064]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5531]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5508]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:1698]
UE4Editor_Core!FWindowsApplication::DeferMessage() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:2120]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:867]
UE4Editor_Core!FWindowsApplication::AppWndProc() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:714]
user32
user32
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:980]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:2977]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [d:\build\++ue4+release-4.15+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll