SetActorLabel() is slow on Landscapes

I've noticed calling SetActorLabel() on a Landscape will call PostEditPropertyChanged() which causes the Landscape Components to regenerate all collisions. As per the repro, this can take a long time on large landscapes.

It seems like changing the label should not cause cause all collisions to be regenerated.

Its a problem since we need to set the name of the output actor and this slows down iteration times for users by quite a bit.

Could the Landscape actor code just ignore this property change?

1. Open Unreal.
2. Create a large landscape in an empty level, say 8161 x 8161
3. Go to the outliner. Rename the landscape actor (F2- > type new name)
4. Observe Unreal hangs for a long time, 10+ seconds for me.

UnrealEditor-Landscape.dll!ULandscapeHeightfieldCollisionComponent::CreateCollisionObject() Line 849 C++
UnrealEditor-Landscape.dll!ULandscapeHeightfieldCollisionComponent::OnCreatePhysicsState() Line 369 C++
UnrealEditor-Engine.dll!UActorComponent::CreatePhysicsState(bool bAllowDeferral) Line 2119 C++
UnrealEditor-Engine.dll!UActorComponent::ExecuteRegisterEvents(FRegisterComponentContext * Context) Line 2205 C++
UnrealEditor-Engine.dll!UActorComponent::RegisterComponentWithWorld(UWorld * InWorld, FRegisterComponentContext * Context) Line 1744 C++
UnrealEditor-Engine.dll!AActor::IncrementalRegisterComponents(int NumComponentsToRegister, FRegisterComponentContext * Context) Line 5931 C++
UnrealEditor-Engine.dll!AActor::RegisterAllComponents() Line 5702 C++
> UnrealEditor-Engine.dll!AActor::PostEditChangeProperty(FPropertyChangedEvent & PropertyChangedEvent) Line 244 C++
UnrealEditor-Landscape.dll!ALandscapeProxy::PostEditChangeProperty(FPropertyChangedEvent & PropertyChangedEvent) Line 6438 C++
UnrealEditor-Landscape.dll!ALandscape::PostEditChangeProperty(FPropertyChangedEvent & PropertyChangedEvent) Line 6995 C++