How to reproduce:
1. Open the project "case_1225888-ListView"
2. Select Tools -> MyEditorWindow in the Menu Bar
3. Observe that the height of each row is 20 pixels in MyEditorWindow
4. Go to the Assets folder in the Project window
5. Open the script "MyEditorWindow"
6. Comment-out line 25 (StepOne) and comment-in line 26 (StepTwo)
7. Save the script
8. Open the Editor again
9. Observe the height of each row in the MyEditorWindow

Expected results: the height of each row in the MyEditorWindow is 60 pixels as set in the script
Actual results: the height of each row in the MyEditorWindow is 20 pixels as before

Reproducible with: 2019.3.0b8, 2019.3.6f1, 2020.1.0a4, 2020.1.0b2, 2020.2.0a3
Not reproducible with: 2019.3.0b7, 2020.1.0a3

Could not test with: 2017.4.38f1, 2018.4.19f1 because the class ListView is not available

Notes:
1. It is not reproducible when ListView.itemHeight is changed and ListView.viewDataKey is set to null (comment-out line 25 and 26 (StepOne, StepTwo) and comment-in line 27 (StepThree) and observe the results)