Steps to reproduce:
1. Create/open any Unity project
2. Create a new empty object and select it in Hierarchy
3. Set object to static by clicking on the Static Checkbox in Inspector
3. Open Static Dropdown menu by clicking on the triangle icon next to the Static checkbox in Inspector
4. Disable every flag individually except "Everything"

Expected result: Static Checkbox shows disabled and checkmark icon next to "Nothing" flag in the dropdown appears
Actual result: Static Checkbox shows enabled and checkmark icon next to "Nothing" flag in the dropdown doesn't appear

Reproducible on: 2021.1.0a4, 2021.1.0a2
Not reproducible on: 2021.1.0a1