X locks after a [alt]-[tab]

[Patrice Dumas]

Hi,

I've just updated a fc1 system to fedora development. I kept the fc1 kernel
(2.4.22-1.2999.nptl) otherwise the system is up to date with fedora
development. I use gnome.

When I hit alt-tab, in order to change window, the other window gets a black
border, a little grey rectangle appears where there used to be the windows
list, but then X is unusable, although I still can move the mouse and see the
pointer move. I can switch to a console.

I have nothing strange in the X log, nothing in dmesg or /var/log/messages. 
Where should I look?

Pat 

Note: I had some problems with my disk and it is possible that a file is
corrupted, but I don't know how to force a fsck of the / filesystem on boot.