Auto expanding textbook crashes Firefox?

Description

Firefox crashed when writing a comment. Reported by :

I did about three lines ... and then it started magically growing then the horrid "not responding" and KILL IT

https://twitter.com/auroraeosrose/status/718813096635015170

Status

Assignee

Unassigned

Reporter

Rob Allen

Labels

None

Epic Name <span class="error">&#91;deprecated, this field is no longer being used&#93;</span>

None

Components

Priority

Major