Comment 2 for bug 382837

Perhaps they intentionally changed the behavior, but that certainly used to be the effect of changing the summary.

I'm pretty sure gmail respects the "References" field in mail headers, which is a way to line up threads even when the subject itself changes. (Consider the Re: New Subject (was old subject) sort of threads anyway.)

Since initial bug reports sometimes have pretty awful summaries, I find it quite useful to change them into something I can actually track without having to actually read the content.