MultipleWindowsApp crashes/freezes in Windows on Snapshot

**Describe the bug**
MultipleWindowsApp crashes/freezes in Windows on Snapshot

**To Reproduce**
Just run the MultipleWindowsApp from cpp examples in Windows and take a Snapshot

**Expected behavior**

**Screenshots**
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**Environment (please complete the following information):**

- Operating system: (Windows 10 64-bit)
- Python version: (e.g. Python 3.6) -> CPP Version
- Open3D version: latest build (shared lib)
- Is this remote workstation?: no
- How did you install Open3D?: build from source)
- Compiler version (if built from source): (e.g. gcc 7.5, clang 7.0) MS Visual Studio 2019
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**Additional context**
Add any other context about the problem here.