A weird bug in Tiger [Upd.]

Two readers told us quite at the same time of a weird issue with Tiger. In both cases, symptoms are identical.

This doubles some lines in the Finder menus, and will cause some strange squares to appear in the windows. All the usual manipulations, zapping PRAM, Resetting Open Firmware, Repairing permissions... won't change anything.
Might have been corrupted preferences, yet the fact the same symptoms will show for two people at the same time renders that highly unlikely.
Looks more like an incompatibility with an installed software or a driver.
It will take a short time for the cause to be determined. Post in our [French] forums if you experience the same.
[Upd.] So, it looks like this menu doubling will occur if you activate the universal access option "VoiceOver". Its accidental activation is easy as it only takes pressing the shortcut Apple-F5.