Comment 282 for bug 113201

This bug affects me too. It usually appears on slow connections like
GPRS or on connections which have some problems with DNS. Also
it appears almost on all connections if i install dnsmasq. But i never
seen it on Ethernet connections.

When firefox hangs it consumes 100% of CPU.

This bug appears when i open new tab, close old, or just switching tabs.
Usually clicking on the links doesn't affect it.

Running firefox -g and beraking during the hang reveals nothing.
It usually breaks in different places but often i see js_Invoke.

It is very annoying per se, but the worst thing about it is the short-living
X Server windows which firefox uses alot. Say if i open new tab and
quickly click on menu "File" firefox opens system-modal menu window
and hangs and the entire X server becomes unusable (does not respond to my actions)
until firefox resumes. I can't switch to another application, the panels do not
respond to my clicks and so on.

The duration of the hang depends on number of open tabs. If i open 50 tabs
it will be about 90 seconds. When i have 10 open tabs it's about 15 seconds.