In 2.8 it was possible to hide the layer you are transforming (with
perspective tool) to get the original out of the way during transform.
In 2.9 you can still hide the layer after transform has begun, but the
transform will fail unless the layer is unhidden before applying the
transform (it fails silently).
Steps to reproduce:
1. Make selection with rectangle (or other) selection tool.
2. Switch to Unified Transform Tool (or Perspective tool, which fails
in the same way)
3. Click to begin transform, then hide the layer (removes
untransformed original so you can see what you are doing).
4. Move control corners to perspective transform the layer as you
5. Hit the Enter key or otherwise apply the transformation.
The transformation fails silently, and you must begin again.
The only solution is to remember to un-hide the layer before applying
A. Make the original hide automatically, making it unnecessary to hide
the layer during transform.
B. Make sure the transformation is applied, regardless of the hidden
state of the layer.
I have also posted this information here:
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