Description

An open but minimized Editor Preferences window causes a memory leak while simulating and repeatedly pressing Play/Stop.

Steps to Reproduce
  1. Create a blank Blueprint project. 
  2. Open Editor Preferences and go to General > Performance and make sure "Show Frame Rate and Memory" is enabled. Do not minimize the preferences window.
  3. From the drop down arrow next to the Play button, select Simulate.
  4. Repeatedly hit Stop and Play for a while and note that memory is correctly released each time you hit Stop.
  5.  Minimize the preference window and repeat step 4. Note that memory consumption climbs by appx 300MB each time you hit Play, but does not get released when hitting stop. You can repeat this until it runs out of memory and crashes, but stop short of running out so you can perform step 6.
  6. Un-minimize the preferences window, then Play and then Stop. Note that most but not all of the memory that was consumed by step 4 now gets released.

 

Expected:

Memory should be released when clicking Stop, regardless of the state of the Editor Preferences window.

Result:

Memory is not released when stopping simulation if the Editor Preference window is open and minimized. Not an issue when open and not minimized.

Callstack
Fatal error: [File:D:/Build/++UE4/Sync/Engine/Source/Runtime/Core/Private/GenericPlatform/GenericPlatformMemory.cpp] [Line: 186] Ran out of memory allocating 832 bytes with alignment 0 UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_Core UE4Editor_Slate UE4Editor_Slate UE4Editor_Slate UE4Editor_Slate UE4Editor_Slate UE4Editor_InputBindingEditor UE4Editor_InputBindingEditor UE4Editor_InputBindingEditor UE4Editor_InputBindingEditor UE4Editor_InputBindingEditor UE4Editor_InputBindingEditor UE4Editor_PropertyEditor UE4Editor_PropertyEditor UE4Editor_PropertyEditor UE4Editor_PropertyEditor UE4Editor_PropertyEditor UE4Editor_PropertyEditor UE4Editor_PropertyEditor UE4Editor_PropertyEditor UE4Editor_InputBindingEditor UE4Editor_Engine UE4Editor_Engine UE4Editor_UnrealEd UE4Editor_UnrealEd UE4Editor UE4Editor UE4Editor UE4Editor UE4Editor kernel32 ntdll

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Unresolved
ComponentGameplay - Input
Affects Versions4.234.24
Target Fix4.25plus
CreatedFeb 3, 2020
UpdatedFeb 4, 2020