Reproduction steps:
1. Open the user's attached project
2. Open Assets > "Cube" Animator Controller
3. Create a Blend Tree
4. Double-click on the Blend Tree
5. Right-click on the Blend Tree and select 'Add Motion'
6. Right-click on the Blend Tree and select 'Add Blend Tree'
7. Double-click on the Blend Tree (that was created in step 6)
8. Undo 2 actions (opening the new Blend Tree and its creation)
9. Observe the Animator window

Expected result: The Blend Tree is fully visible
Actual result: The Blend Tree is shrunk

Reproduced with: 2021.2.0b1, 2021.3.0f1, 2022.1.0b16, 2022.2.0a10
Not reproduced with: 2019.4.38f1, 2020.3.33f1, 2021.2.0a21

Notes:
- From 2022.1.0a12 Blend Tree is shrunk
- From 2021.2.0b1 to 2022.1.0a11 when undoing Blend Tree is not visible