1) Open the attached project
2) Open two inspector windows
3) In the Project window, click on TestAsset
4) See that both inspector windows display a SomeString field (this field is drawn by a custom inspector -TestAssetDrawer- using CreateInspectorGUI)
5) Click on the Editor folder (or any folder)
6) Click on TestAsset again

Result: Only one Inspector is drawing the SomeString field. The other inspector does not draw anything. (see screenshots)
Expected: Both inspectors should draw the SomeString field.

Reproduced on:
2019.1.0b2 2019.1.2f1 2019.2.0b1 2019.3.0a2

Not reproduced on:
2019.1.0b1