Property Editor Setter is an Unreal Engine editor module that ensures surface (top-level) property setters are invoked when any nested property is modified in the Details panel, including properties inside structs, instanced structs, arrays, maps, and sets.

In Unreal Engine, properties can be marked with the Setter metadata specifier to define a setter function. However, Unreal's property editor is inconsistent about invoking these setters:

• Some container types (certain arrays, maps, sets) may invoke setters.
• Many property types never invoke their setters regardless of the metadata.
• Even when supported, not all edit actions trigger setter calls.

There's no reliable pattern - it varies by property type and edit context.

This means that even though your UPROPERTY has valid Setter metadata, the setter may never be called when editing in the Details panel. This leads to:

• Validation logic being bypassed.
• Dependent properties not updating.
• Inconsistent object state.

This module takes complete control of setter invocation by:

1. Intercepting ALL property edits in the editor via OnPreObjectPropertyChanged / OnObjectPropertyChanged delegates.
2. Capturing the original value of any surface property that has a valid setter.
3. Allowing the engine to apply the change normally.
4. Restoring the original value temporarily.
5. Manually invoking the property setter with the new value.
6. Cleaning up all allocated memory.

The module provides consistent, predictable setter invocation across all property types and edit scenarios.

• Intercepts all property edits in the editor.
• Manually calls setters for any property type with valid Setter metadata.
• Works regardless of nesting (structs, instanced structs, containers, containers of containers, etc).
• Works for all edit actions (direct edit, add, remove, reset to default, etc).

• Measures setter execution time via custom stat: STAT_PropertyEditorSetter.
• Useful for identifying performance bottlenecks in setter functions.

Settings accessible via Project Settings → Property Setter Settings:

Editor.ForceCallSettersOnPropertyEdit  // Toggle feature on/off
Editor.LogSurfaceProperties            // Toggle debug logging

Allows excluding specific classes from automatic setter invocation:

• Can exclude exact classes only.
• Can exclude classes and all subclasses.
• Useful for performance-sensitive or incompatible classes.

UPROPERTY(EditAnywhere, meta = (Setter = "SetMyStruct"))
FMyStructure MyStruct;

UFUNCTION(BlueprintCallable)
void SetMyStruct(FMyStructure& MyNewStruct);

MyStruct will have its setter called, where data validation, sanitization and even rejection can happen. Your code is the limit! Note: Setters need to be BlueprintCallable!

PropertyEditorSetter/
├── PropertyEditorSetterModule.h/cpp    // Core module implementation
├── PropertyEditorSetter.h/cpp          // Helper utilities and namespace
├── PropertyEditorSetterSettings.h/cpp  // Configuration settings
└── PropertyEditorSetter.Build.cs       // Build configuration

1. Validates the object and property chain.
2. Extracts the changing property (tail) and surface property (head).
3. Checks if the surface property has a setter.
4. Verifies the object's class isn't blacklisted.
5. Allocates memory and captures the current surface property value.
6. Stores a data instance for post-change processing.

1. Finds the matching cached instance.
2. Captures the new (modified) value of the surface property.
3. Restores the original value to the surface property.
4. Calls the surface property's setter with the new value.
5. Measures execution time for performance tracking.
6. Cleans up memory and removes the instance.

The build configuration automatically adjusts module dependencies based on engine version.

• Only works in the editor (not at runtime).
• Requires properties to have Setter metadata.
• Some performance overhead (allocates/deallocates temporary snapshots for each property edit, copies data a few times per edit). Not noticeable in most cases, but worth noting.

Created by Jorge David López Caraballo GitHub: Lokillouu

All rights reserved to Jorge David López Caraballo