If a child blueprint class has an Instanced/EditInlineNew object property, that property will always be detected as changed by the property editor (i.e. it will show a "Revert" arrow on that property), even if its properties are identical to the parent.

UE - Framework - Blueprint Editor - Dec 17, 2025

Context: Blueprint classes can use Instanced/EditInlineNew object property specifiers to create and edit subobjects directly in the editor. Problem: If a child blueprint class has an Instanced/Edit ...

SelectActorsUsingThisAsset doesn't select actors that are referenced by an array and using a Scene component as root

Tools - Sep 11, 2015

SelectActorsUsingThisAsset doesn't select actors that are referenced by an array and using a Scene component as root User Description: I have a BP with editable actor references array. Recently I ...

Possible data loss/corruption when loading levels in editor

UE - Gameplay - Jul 18, 2018

Reported behavior: Given Level_A which contains object_X, where object_X references Level_BDeleting object_X causes AssetRenameManger to check if we need to patch up other levelsLevel_B is load ...

A Blueprint containing an array Swap node will fail to be nativized.

UE - Gameplay - Blueprint - Jul 17, 2020

Blueprint assets that utilize an array "swap" node to swap elements cannot currently be converted to C++. Current workaround: Either avoid use of the "swap" node or exclude the Blueprint asset from ...

Alt-tabbing out of a Standalone App or packaged version of a game does not trigger LostFocus or ReceiveFocus

Tools - Sep 9, 2015

If a user uses Alt-tab to change to another window, the ReceivedFocus and LostFocus functions are not called as they would usually be called when using something such as Shift+F1 or Ctrl+Esc. Note: ...

OSVR fatal error while playing in -game

UE - Platform - XR - May 6, 2016

Found on: //UE4/Dev-VR CL-2967563 About 1/6th of the time I'd start a -game instance and go in to stereo on the OSVR, the game would seemingly just close itself. I say close as opposed to crash, si ...

Struct with a single unaltered element will remove the element from the struct on compile

UE - Gameplay - Blueprint - Oct 7, 2015

If used inside a UMG Blueprint, a struct that has only one element will remove the element from the struct after compiling the blueprint. If the element is edited or a second element is added then ...

Blueprints not marked dirty when variables in referenced actors are renamed

UE - Gameplay - Blueprint Compiler - Feb 20, 2018

Blueprints using renamed variable do not indicate that they need to be recompiled. (However errors are shown on play) It is possible to not see an error if you add a variable with the same name as ...

Crash in NaniteStreamManager when Nanite data fails to decode corrupt data from DDC

UE - Graphics Features - Nanite - Sep 11, 2024

If Nanite data becomes corrupt in the DDC, the Editor may crash in FStreamingManager::InstallReadyPages() when the Pending.State is FPendingPage::EState::DDC_Ready but the resulting SrcPtr is null b ...