Threading - why does it keep coming back? I have just realised it's back again on my Thunderbird and I never knowingly turned it back on. Why does Mozilla keep trying to force it on users? This has been an annoyance for users for several years now and the message has still not got through it would seem. For an open and user-facing organisation, this is strange behaviour that I just do not comprehend. Include it if you want, but make it optional and easily so. I know this is only the community forum, not Mozilla, but one would think that a wise organisation would keep an eye on what their customers were saying & feeling.