This is a common crash affecting Mac users in 4.16. It has occurred since at least 4.13
User Descriptions
UE4Editor-Kismet.dylib!FTabInfo::OnMouseDownHisory(FGeometry const&, FPointerEvent const&, TWeakPtr<SMenuAnchor,() UE4Editor-Kismet.dylib!TBaseSPMethodDelegateInstance<false, FTabInfo, (ESPMode)0, FReply (FGeometry const&, FPointerEvent const&), TWeakPtr<SMenuAnchor, (ESPMode)0> >::Execute() UE4Editor-SlateCore.dylib!SWidget::OnMouseButtonDown() UE4Editor-Slate.dylib!FSlateApplication::RoutePointerDownEvent() UE4Editor-Slate.dylib!FSlateApplication::ProcessMouseButtonDownEvent(TSharedPtr<FGenericWindow,() UE4Editor-Slate.dylib!FSlateApplication::OnMouseDown(TSharedPtr<FGenericWindow,() UE4Editor-Core.dylib!FMacApplication::ProcessMouseDownEvent(FDeferredMacEvent const&, TSharedPtr<FMacWindow,() UE4Editor-Core.dylib!FMacApplication::ProcessEvent() UE4Editor-Core.dylib!FMacApplication::ProcessDeferredEvents() UE4Editor-Slate.dylib!FSlateApplication::TickPlatform() UE4Editor-Slate.dylib!FSlateApplication::Tick() UE4Editor!FEngineLoop::Tick() UE4Editor!GuardedMain() UE4Editor!<Unknown> UE4Editor-Core.dylib!<Unknown> Foundation!Unknown() libsystem_pthread.dylib!<Unknown> libsystem_pthread.dylib!<Unknown> libsystem_pthread.dylib!<Unknown>
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-47546 in the post.