More fixing everything

Source/Integration/PlayerControllerBase.cpp

@@ -164,7 +164,7 @@ void AlxPlayerControllerBase::AddWidgetToRoot(UUserWidget *Widget)
 	if (Widget->GetParent() == PC->RootCanvas) return;
 
 	UlxRootCanvasSlot *Slot = PC->RootCanvas->AddChildToRootCanvas(Widget);
-	Slot->SetZOrder(0);
+	Slot->SlotUnderConstruction = false;
 }
 
 void AlxPlayerControllerBase::BuildInputStack(TArray<UInputComponent*>& InputStack)
@@ -256,10 +256,6 @@ void AlxPlayerControllerBase::BuildInputStack(TArray<UInputComponent*>& InputSta
 
 void AlxPlayerControllerBase::UpdateInputMode()
 {
-	// Drain any deferred ZOrder writes from SetWidgetWindowManagement
-	// before we read the front-most slot.
-	RootCanvas->PropagateZOrderToSlate();
-
 	// Get all the various objects we need to be able to manipulate
 	// the input mode.
 	UGameViewportClient *GameViewportClient = GetWorld()->GetGameViewport();

Source/Integration/RootCanvas.cpp

@@ -18,6 +18,34 @@ UlxRootCanvasSlot::UlxRootCanvasSlot(const FObjectInitializer& ObjectInitializer
 	SetOffsets(FMargin(0.0f, 0.0f, 0.0f, 0.0f));
 }
 
+void UlxRootCanvasSlot::SetZOrderReliable(int32 Order)
+{
+	if (SlotUnderConstruction)
+	{
+		PRAGMA_DISABLE_DEPRECATION_WARNINGS
+		ZOrder = Order;
+		PRAGMA_ENABLE_DEPRECATION_WARNINGS
+	}
+	else
+	{
+		SetZOrder(Order);
+	}
+}
+
+int32 UlxRootCanvasSlot::GetZOrderReliable()
+{
+	if (SlotUnderConstruction)
+	{
+		PRAGMA_DISABLE_DEPRECATION_WARNINGS
+		return ZOrder;
+		PRAGMA_ENABLE_DEPRECATION_WARNINGS
+	}
+	else
+	{
+		return GetZOrder();
+	}
+}
+
 UClass* UlxRootCanvasPanel::GetSlotClass() const
 {
 	return UlxRootCanvasSlot::StaticClass();
@@ -49,23 +77,11 @@ int32 UlxRootCanvasPanel::GetMaxZOrder() const
 	{
 		UlxRootCanvasSlot *TypedSlot = Cast<UlxRootCanvasSlot>(PanelSlot);
 		check(TypedSlot);
-		MaxZOrder = FMath::Max(MaxZOrder, TypedSlot->GetZOrder());
+		MaxZOrder = FMath::Max(MaxZOrder, TypedSlot->GetZOrderReliable());
 	}
 	return MaxZOrder;
 }
 
-void UlxRootCanvasPanel::PropagateZOrderToSlate()
-{
-	if (!MustPropagateZOrderToSlate) return;
-	MustPropagateZOrderToSlate = false;
-	for (UPanelSlot *PanelSlot : Slots)
-	{
-		UlxRootCanvasSlot *TypedSlot = Cast<UlxRootCanvasSlot>(PanelSlot);
-		check(TypedSlot);
-		TypedSlot->SetZOrder(TypedSlot->GetZOrder());
-	}
-}
-
 TArray<UlxRootCanvasSlot*> UlxRootCanvasPanel::GetSortedUserWidgets()
 {
 	TArray<UlxRootCanvasSlot*> Result;
@@ -105,17 +121,6 @@ void UlxRootCanvasPanel::SetWidgetWindowManagement(class UUserWidget *Widget,
 	Slot->BlockInput = BlockInput;
 	Slot->EnableEnhancedInput = EnableEnhancedInput;
 	Widget->SetDesiredFocusWidget(DesiredFocusWidget);
-	if (BringToFront)
+	if (BringToFront) Slot->SetZOrderReliable(Panel->GetMaxZOrder() + 1);
-	{
-		// Write the int32 ZOrder UPROPERTY directly and defer the
-		// Slate-side push to PropagateZOrderToSlate. Going through SetZOrder
-		// here is unsafe when called from Event Construct: the FSlot
-		// has been Exposed but its Owner isn't set yet, which fires
-		// an ensure in SConstraintCanvas::FSlot::SetZOrder.
-		PRAGMA_DISABLE_DEPRECATION_WARNINGS
-		Slot->ZOrder = Panel->GetMaxZOrder() + 1;
-		PRAGMA_ENABLE_DEPRECATION_WARNINGS
-		Panel->MustPropagateZOrderToSlate = true;
-	}
 }
 

Source/Integration/RootCanvas.h

@@ -59,6 +59,22 @@ public:
 	// events in the Event Graph are deactivated.
 	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Luprex|Input Mode")
 	bool EnableEnhancedInput = true;
+
+	// Knowing whether the slot is under construction helps us to work
+	// around some bugs in Unreal.  See below.
+	bool SlotUnderConstruction = true;
+	
+	// Reliable version of SetZOrder.  There is a bug in the normal version of
+	// SetZOrder: it crashes if you use it during OnConstruct.  We have a
+	// workaround, but it requires using a different getter and setter.
+	UFUNCTION(BlueprintCallable, Category = "Luprex|Input Mode")
+	void SetZOrderReliable(int32 Order);
+
+	// Reliable version of GetZOrder.  There is a bug in the normal version of
+	// SetZOrder: it crashes if you use it during OnConstruct.  We have a
+	// workaround, but it requires using a different getter and setter.
+	UFUNCTION(BlueprintCallable, Category = "Luprex|Input Mode")
+	int32 GetZOrderReliable();
 };
 
 ////////////////////////////////////////////////////////////
@@ -91,13 +107,6 @@ public:
 	// Used as the basis for placing new widgets on top.
 	int32 GetMaxZOrder() const;
 
-	// SetZOrder is buggy: if you call it inside Event Construct,
-	// it crashes.  So we've developed a hack to make it reliable.  
-	// To set the zorder, you store the value in the slot property,
-	// without calling SetZorder.  This routine, which is used later,
-	// propagates that value into the slate widgets.
-	void PropagateZOrderToSlate();
-
 	// This function updates several window-management-related properties
 	// which are stored in the UserWidget and the lxRootCanvasSlot.  Note that
 	// it is perfectly legal to edit these properties by other means: this
@@ -122,10 +131,6 @@ protected:
 
 	// UPanelWidget
 	virtual UClass* GetSlotClass() const override;
-
-public:
-
-	bool MustPropagateZOrderToSlate = false;
 };