Editor will crash when Blueprint Details Panel is dragged across the Event Graph

When dragging the Details Panel in a Blueprint across the event graph the editor will crash.

[Link Removed]

1. Open UE4 (First Person Template)
2. Open FirstPersonCharacter BP
3. Drag Details Panel into Event Graph viewport
4. Should crash now

Results: The editor will crash if the Details panel tab is dragged over the center viewport graph.

Expected: The details panel should dock in any part of the BP UI.

MachineId:621DFBAB44A9B51A4245D5A61065407D
EpicAccountId:7c6293d6bf1940c0bc89e1494c5ba9d7

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

"Assertion failed: IsValid() [Link Removed] [Line: 698]
"

KERNELBASE
UE4Editor_Core!FOutputDeviceWindowsError::Serialize() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor_Core!FOutputDevice::Logf__VA() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\misc\outputdevice.cpp:144]
UE4Editor_Core!FDebug::AssertFailed() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\misc\outputdevice.cpp:360]
UE4Editor_Slate!FTabManager::DrawAttention() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\private\framework\docking\tabmanager.cpp:849]
UE4Editor_Slate!FTabManager::InvokeTab_Internal() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\private\framework\docking\tabmanager.cpp:928]
UE4Editor_Slate!FTabManager::InvokeTab() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\private\framework\docking\tabmanager.cpp:879]
UE4Editor_Kismet!FBlueprintEditor::TryInvokingDetailsTab() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\kismet\private\blueprinteditor.cpp:7625]
UE4Editor_Kismet!FBlueprintEditor::OnSelectionUpdated() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\kismet\private\blueprinteditor.cpp:820]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,TTypeWrapper<void> __cdecl(TArray<TSharedPtr<FSCSEditorTreeNode,0>,FDefaultAllocator> const & __ptr64)>::Execute() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:282]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,void __cdecl(TArray<TSharedPtr<FSCSEditorTreeNode,0>,FDefaultAllocator> const & __ptr64)>::ExecuteIfSafe() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:388]
UE4Editor_Kismet!SSCSEditor::OnTreeSelectionChanged() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\kismet\private\sscseditor.cpp:5133]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,SSCSEditor,0,TTypeWrapper<void> __cdecl(TSharedPtr<FSCSEditorTreeNode,0>,enum ESelectInfo::Type)>::Execute() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:282]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,SSCSEditor,0,void __cdecl(TSharedPtr<FSCSEditorTreeNode,0>,enum ESelectInfo::Type)>::ExecuteIfSafe() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:388]
UE4Editor_Kismet!TBaseDelegate<void,TSharedPtr<FSCSEditorTreeNode,0>,enum ESelectInfo::Type>::ExecuteIfBound() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:519]
UE4Editor_Kismet!SListView<TSharedPtr<FSCSEditorTreeNode,0> >::Private_SignalSelectionChanged() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\public\widgets\views\slistview.h:609]
UE4Editor_Kismet!SListView<TSharedPtr<FSCSEditorTreeNode,0> >::SetItemSelection() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\slate\public\widgets\views\slistview.h:996]
UE4Editor_Kismet!SSCSEditor::UpdateTree() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\kismet\private\sscseditor.cpp:4378]
UE4Editor_Kismet!FBlueprintEditor::UpdatePreviewActor() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\kismet\private\blueprinteditor.cpp:7355]
UE4Editor_Kismet!FBlueprintEditor::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\kismet\private\blueprinteditor.cpp:6330]
UE4Editor_UnrealEd!FTickableEditorObject::TickObjects() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\public\tickableeditorobject.h:15]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\editorengine.cpp:1111]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\unrealedengine.cpp:362]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launchengineloop.cpp:2355]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:249]