Reproduction steps:
1. Open the attached project "ReproProj"
2. Select “New TileSet” in the Project window
3. In Inspector, change “Cell Sizing” to “Manual”
4. Change Cell Size values
5. Select the Apply button at the bottom
6. Observe changes in Cell Sizing

Expected result: Cell Sizing mode and Cell Size Inspector values should not reset after applying changes
Actual result: Values are reset to Automatic and Cell Size to (1,1,0)

Reproducible with: 6000.2.10f1, 6000.3.0b7, 6000.4.0a4
Could not test with: 6000.0.62f1 (“New TileSet“ does not open in Inspector)

Testing environment: Windows 10 Enterprise 21H2
Not reproducible on: No other environment tested