How to reproduce:
1. Create and open a new 3D project
2. Navigate to Window → Package Management → Package Manager
3. In “Unity Registry“, search for “Multiplayer Play Mode“ and install the package
4. Navigate and open the Window → Multiplayer → Multiplayer Play Mode window
5. Dock the Window anywhere in the Editor
6. Navigate to “Select editor layout“ in the top right
7. Select “Save Layout…“
8. In the window that pops up, enter any name and click create
9. Observe the Console tab
10. Navigate to “Select editor layout“ in the top right and change the Layout to any other
11. Switch back to the saved Layout from step 8
12. Observe the Editor

Actual result: “Multiplayer Play Model” docked window disappears
Expected result: “Multiplayer Play Model” docked window appears in the same position it was when the layout was saved

Reproducible with: 2.0.0-pre.1 (6000.3.6f1, 6000.4.0b6, 6000.5.0a5), 2.0.1 (6000.3.6f1, 6000.4.0b6, 6000.5.0a5)
Not reproducible with: 1.6.3 (6000.3.6f1, 6000.4.0b6, 6000.5.0a5)

Reproducible on: Ubuntu 22.04, Windows 11, macOS 26.2 (M1 Silicon)
Could not reproduce on: No other environment tested

Note: After saving or deleting the Layout (in package versions 1.6.3, 2.0.0-pre.1 and 2.0.1), the following error message occurs:
”AssertionException: Assertion failure. Values are not equal.
Expected: 4 == 3”