URL: https://drive.google.com/drive/u/0/my-drive

Browser / Version: Firefox 60.0
Operating System: Windows 10
Tested Another Browser: Yes

Problem type: Something else
Description: Using the arrow keys and backspace key to navigate text in Google docs/slide does not work. Tested this on Internet Explorer and it worked fine, so it seems to be a problem related to Firefox.
Steps to Reproduce:

gfx.webrender.all: false
gfx.webrender.blob-images: 1
gfx.webrender.enabled: false
image.mem.shared: 2

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