Inconsistently broken with extensions.interposition.enabled disabled and e10s enabled.

[mzso]

Hi!

I started testing with "extensions.interposition.enabled" which disabled compatibility shims for addons.

The result is weird with this addon. Sometimes it's alright sometimes the urls of two tabs are mixed:

Klicking the segment loads the segment of whichever website it belongs to "correctly".

Sometimes it's broken: Only shows only one incomplete segment, for example "youtube.c" or such, and when clicked opens a new tab with that url. Sometimes it's empty and does nothing.