Segmentation fault with "high" security when changing in about:addons to "Extensions" or "Appearance"

Tor-Browser version: 7.0a3-build4, 64 bit Linux

The segmentation fault is maybe only the most annoying part of the underlying issue. If the security level is set to "High" and after a restart of Tor Browser, opening about:addons and trying to change to the "Extensions" or "Appearance" panel leads to a segmentation fault.

Other effects of setting the security level to "High" which may be related or may help you finding the root cause: (after closing and restarting)

• the symbols in front of the panel descritions in about:preferences are not visible
• the checkboxes in about:preferences don't show a check mark or a dot if they are selected

Unfortunately I don't know how to debug this, but I hope you can reproduce this easily.

Trac:
Username: viktorj