Crash when returning to viewport from immersive mode with an editor window tabbed beneath

When the user enters immersive mode by hitting f11 and then opens the material editor, (which opens tabbed in the editor underneath the immersive display)The engine crashes when hitting attempting to return from immersive mode using f11.

[Link Removed]

Crash Reporter Logs included:
MachineId:6B2BB2FC4D1CA12D1FE62D99CA121FC9
EpicAccountId:47ed51f3f6034c9eab40f1457d0858ea

Unknown exception - code 00000001 (first/second chance not available)

Assertion failed: IsValid() [Link Removed] [Line: 658]

KERNELBASE + 37901 bytes
UE4Editor_Core!FOutputDeviceWindowsError::Serialize() + 292 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor_Core!FOutputDevice::Logf__VA() + 248 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:144]
UE4Editor_Core!FDebug::AssertFailed() + 1079 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:224]
UE4Editor_LevelEditor!FLevelViewportLayout::MaximizeViewport() + 1275 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\leveleditor\private\levelviewportlayout.cpp:381]
UE4Editor_LevelEditor!FLevelViewportLayout::Tick() + 278 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\leveleditor\private\levelviewportlayout.cpp:685]
UE4Editor_UnrealEd!FTickableEditorObject::TickObjects() + 164 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\public\tickableeditorobject.h:15]
UE4Editor_UnrealEd!UEditorEngine::Tick() + 1635 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\editor.cpp:1110]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() + 22 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\editor\unrealed\private\unrealedengine.cpp:347]
UE4Editor!FEngineLoop::Tick() + 4179 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:2257]
UE4Editor!GuardedMain() + 1404 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

1. Download 4.7.1 official build
2. Create a First Person project with starter content
3. Open content browser,
4. Press F11 to maximize main viewport
5. Open material editor, the material editor window will slide under the main viewport
6. Press F11 to return main viewport from immersive mode.

Expected: viewport will be returned to initial viewing mode, no errors or crashes
Actual: Crash