Adding an element to an array in the Material Editor automatically collapses all expanded elements in the array.
I've successfully reproduced this issue with the following nodes:

  • LandscapeGrassOutput
  • LandscapeLayerBlend

I'm able to reproduce this issue as far back as the live 4.20.3 Binary (CL 4377374). I cannot reproduce in the live 4.19.2 Binary (CL 4033788).

It is therefore marked as a regression.

Steps to Reproduce
  1. Open any project in UE4Editor
  2. Create a a new Material
  3. Open the newly-created Material
  4. Right-click within the graph
  5. Search for and select a LandscapeGrassOutput node
  6. In the Material Editor Details Panel, expand Element 0
  7. In the Material Editor Details Panel, add a new element to the Grass Types array

The Grass Types array collapses all elements when a new element is addd

Expected Result:
Expanded elements are not collapsed when a new element is added

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ComponentUE - Rendering - Materials
Affects Versions4.
Target Fix4.23
Fix Commit5838779
Main Commit6666942
CreatedApr 3, 2019
ResolvedJun 4, 2019
UpdatedNov 2, 2021