refresh my memory -- why firefox goes grey and inactive?

[Colin Law]

On 26 June 2010 10:45, Robert P. J. Day <rpjday at crashcourse.ca> wrote:
>
>  yes, yes, i know, we've had this dicsussion before but i just
> installed ubuntu 10.04 on a new laptop and, over five minutes ago, my
> two firefox sessions suddenly went grey and unresponsive and i know
> there was a simple solution in terms of deselecting a setting but i
> can't remember what it is, and it's still a bit aggravating that it
> happens in the first place -- that is, that firefox is suddenly
> waiting on some event for, literally, minutes.  weird.

The original thread is at
http://osdir.com/ml/ubuntu-users/2010-05/msg01576.html or
https://lists.ubuntu.com/archives/ubuntu-users/2010-May/218498.html

I think the conclusion was that the system is running out of resources
(possibly RAM), but read through for other suggestions.

Colin