firefox 46

[#1]

I've done a bit more homework on this and I've a suspicion it's related to this RFC and the bug report filed here.

If that is the case though, we're in for quite a wait

A Mozilla Bugmaster said:
Tracking for 46+.
I can keep an eye on it but it seems unlikely this will be fixed before 47 comes out (June 7th)

Edit: looks like this is affecting the Plusnet Webmail platform too

[#2 · Accepted solution]

Firefox 47 is now available.

[#3]

Thanks Bob.