Example: Cut something to the clipboard in Firefox.

Close Firefox.

Try to paste into a GNOME application.

Ta-DA! Look ma! No data!

That's the bug.

Lather, rinse and repeat for GNOME/KDE pasting, too. Although there are moves afoot to develop a common clipboard, the movers and shakers (of which the aforementioned Mr Nickell is one) are apparently easily distracted by shiny things.