Reproduction steps:
1. Create a new project
2. Create a Tilemap game object
3. Add Grid component to Layer game object (which is a child of Tile Map)
4. Remove that Grid component
5. Change the layout through Window -> Layouts

Expected: Layout changes
Actual: Layout changes, scene window is greyed out, if it has tabs - they are inaccessible.

Workaround: Click on the scene window, or enter and exit play mode

Reproduced on: 5.5.0x3-2D

Might be difficult to reproduce, because removing grid component sometimes crashes on 5.5.0x3-2D

Fixed on: 2017.2.0a4