Closing the GPU Visualizer window on Linux causes the editor to crash

After opening the GPU Visualizer window, pressing the "X" to close the window causes the editor to crash.

1. Open UE4Editor (any project)
2. Use ctrl+shift+comma to open GPU Visualizer window
3. Press the "X" to close the window

Result:
Editor crashes immediately

[2015.10.21-19.06.11:701][437]LogLinux: === Critical error: ===
Unhandled Exception: SIGSEGV: invalid attempt to access memory at address 0x00000000

[2015.10.21-19.06.11:701][437]LogLinux: Fatal error!

[Callstack] 02 0x00007fb1270706fb ReportCrash(FLinuxCrashContext const&)
[Callstack] 03 0x000000000043015b EngineCrashHandler(FGenericCrashContext const&) [/home/doug/Documents/github/4.9/Engine/Source/Runtime/Launch/Private/Linux/LaunchLinux.cpp, line 31]
[Callstack] 04 0x00007fb127074738 PlatformCrashHandler(int, siginfo_t*, void*)
[Callstack] 05 0x00007fb127b68d10 /lib/x86_64-linux-gnu/libpthread.so.0(+0x10d10) [0x7fb127b68d10]
[Callstack] 06 0x00007fb118ac8132 STimeline::~STimeline()
[Callstack] 07 0x00007fb118ac83a9 STimeline::~STimeline()
[Callstack] 08 0x00007fb12077f466 FSlotBase::~FSlotBase()
[Callstack] 09 0x00007fb12416ef54 TIndirectArray<SBoxPanel::FSlot, FDefaultAllocator>::Empty(int)
[Callstack] 10 0x00007fb12416ee8e TIndirectArray<SBoxPanel::FSlot, FDefaultAllocator>::~TIndirectArray()
[Callstack] 11 0x00007fb1224e7fee SVerticalBox::~SVerticalBox()
[Callstack] 12 0x00007fb12077f466 FSlotBase::~FSlotBase()
[[2015.10.21-19.06.11:702][437]LogExit: Executing StaticShutdownAfterError
Starting ../../../engine/binaries/linux/crashreportclient
[2015.10.21-19.06.11:705][437]LogGenericPlatformMisc: FPlatformMisc::RequestExit(1)