Unreal Engine Issues and Bug Tracker (UE-319330)

Description

Create an asset containing a RetainerBox in UMG, then add the created UMG to the viewport using AddViewport. Running MRQ after this causes a crash.

Steps to Reproduce

Open the attached project in the editor.
Open "NewLevelSequencer" Sequencer asset.
Open "Movie Render Queue" window in sequence editor.
Press "Rneder (Remote)" button.

Then, crash the editor.

Callstack

LogStats: FPlatformStackWalk::StackWalkAndDump -  0.201 s
LogOutputDevice: Error: === Handled ensure: ===
LogOutputDevice: Error: 
LogOutputDevice: Error: Ensure condition failed: SameSize(AppendedGrid.Get())  [File:D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Input\HittestGrid.cpp] [Line: 939] 
LogOutputDevice: Error: 
LogOutputDevice: Error: Stack: 
LogOutputDevice: Error: [Callstack] 0x00007ffbeba1a1ce UnrealEditor-SlateCore.dll!FHittestGrid::GetCollapsedHittestGrid() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Input\HittestGrid.cpp:939]
LogOutputDevice: Error: [Callstack] 0x00007ffbeba1a592 UnrealEditor-SlateCore.dll!FHittestGrid::GetCollapsedWidgets() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Input\HittestGrid.cpp:968]
LogOutputDevice: Error: [Callstack] 0x00007ffbeba256e5 UnrealEditor-SlateCore.dll!FHittestGrid::GetHitIndexFromCellIndex() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Input\HittestGrid.cpp:873]
LogOutputDevice: Error: [Callstack] 0x00007ffbeba18a36 UnrealEditor-SlateCore.dll!FHittestGrid::GetBubblePath() [D:\build\++UE5\Sync\Engine\Source\Runtime\SlateCore\Private\Input\HittestGrid.cpp:187]
LogOutputDevice: Error: [Callstack] 0x00007ffc90ddd1f6 UnrealEditor-Slate.dll!FSlateApplication::LocateWidgetInWindow() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1846]
LogOutputDevice: Error: [Callstack] 0x00007ffc90ddd63e UnrealEditor-Slate.dll!FSlateApplication::LocateWindowUnderMouse() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:1095]
LogOutputDevice: Error: [Callstack] 0x00007ffc90df1b12 UnrealEditor-Slate.dll!FSlateApplication::ProcessMouseMoveEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:6188]
LogOutputDevice: Error: [Callstack] 0x00007ffc90de3d85 UnrealEditor-Slate.dll!FSlateApplication::OnMouseMove() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:6117]
LogOutputDevice: Error: [Callstack] 0x00007ffd1564f72b UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:3092]
LogOutputDevice: Error: [Callstack] 0x00007ffd15637137 UnrealEditor-ApplicationCore.dll!FWindowsApplication::DeferMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:3570]
LogOutputDevice: Error: [Callstack] 0x00007ffd1565299c UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2725]
LogOutputDevice: Error: [Callstack] 0x00007ffd15631171 UnrealEditor-ApplicationCore.dll!FWindowsApplication::AppWndProc() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:1722]
LogOutputDevice: Error: [Callstack] 0x00007ffdb82d83f1 USER32.dll!UnknownFunction []
LogOutputDevice: Error: [Callstack] 0x00007ffdb82d7eb1 USER32.dll!UnknownFunction []
LogOutputDevice: Error: [Callstack] 0x00007ffd15672316 UnrealEditor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsPlatformApplicationMisc.cpp:145]
LogOutputDevice: Error: [Callstack] 0x00007ff60319871b UnrealEditor.exe!FEngineLoop::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5554]
LogOutputDevice: Error: [Callstack] 0x00007ff6031be5ac UnrealEditor.exe!GuardedMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:187]
LogOutputDevice: Error: [Callstack] 0x00007ff6031be6ba UnrealEditor.exe!GuardedMainWrapper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:128]
LogOutputDevice: Error: [Callstack] 0x00007ff6031c209e UnrealEditor.exe!LaunchWindowsStartup() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:282]
LogOutputDevice: Error: [Callstack] 0x00007ff6031d4e44 UnrealEditor.exe!WinMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:339]
LogOutputDevice: Error: [Callstack] 0x00007ff6031d80fa UnrealEditor.exe!__scrt_common_main_seh() [D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
LogOutputDevice: Error: [Callstack] 0x00007ffdb947259d KERNEL32.DLL!UnknownFunction []
LogOutputDevice: Error: [Callstack] 0x00007ffdb9d6af38 ntdll.dll!UnknownFunction []
LogOutputDevice: Error:

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Unresolved

Component	UE - Editor - UI Systems - Slate
Affects Versions	5.6
Target Fix	5.7

Created	Sep 9, 2025
Updated	Sep 10, 2025

View Jira Issue

UE-319330

Crashes occur when executing MRQ while adding UMG with RetainerBox.

Crashes occur when executing MRQ while adding UMG with RetainerBox.

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