How to reproduce:
1. Download and open attached "NavMesh_Bug4" project
2. Switch Layout to "Nice"
3. Switch Layout to Default

Expected result: Console is empty
Actual result: Error is thrown in the Console

Reproduced with: 2017.4.11f1, 2018.1.9f2, 2018.2.8f1, 2018.3.0b1

Error:
Failed to destroy views: #1
HostView
UnityEngine.DebugLogHandler:Internal_Log(LogType, String, Object)
UnityEngine.DebugLogHandler:LogFormat(LogType, Object, String, Object[])
UnityEngine.Logger:Log(LogType, Object)
UnityEngine.Debug:LogError(Object)
UnityEditor.WindowLayout:CloseWindows() (at C:\buildslave\unity\build\Editor\Mono\GUI\WindowLayout.cs:710)
UnityEditor.WindowLayout:LoadWindowLayout(String, Boolean) (at C:\buildslave\unity\build\Editor\Mono\GUI\WindowLayout.cs:492)