System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 451.48

Blender Version
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-08-23 06:32, hash: rBed288a5786d6

Short description of error
Activating Preview as Backdrop in the Sequencer view type will crash Blender to desktop.

Exact steps for others to reproduce the error
[Please describe the exact steps needed to reproduce the issue]
[Based on the default startup or an attached .blend file (as simple as possible)]

Open Blender
Switch to Sequencer workspace.
Add a strip (not required, but was a test if it crashes with a strip type too)
In the View menu tick Preview as Backdrop.
Crash.