Working on new root canvas stuff

Source/Integration/RootCanvas.h

@@ -91,6 +91,13 @@ 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
@@ -115,6 +122,10 @@ protected:
 
 	// UPanelWidget
 	virtual UClass* GetSlotClass() const override;
+
+public:
+
+	bool MustPropagateZOrderToSlate = false;
 };