Debian 6.0 Squeeze + Unstable & Experimental Packages.
Linux version 3.4.9-64 (root@eeepc) (gcc version 4.7.1 (Debian 4.7.1-6) ) #32 SMP PREEMPT Fri Aug 17 03:19:19 CEST 2012
java version "1.6.0_24" 32-bit - OpenJDK IcedTea
This is a strange glitch happening to me in SMP.
See Screenshot one:
You will see a Diamond Pickaxe - striking 3 times leads to its destruction.
After that, I opened my inventory and dragged the Diamond Pickaxe of screenshot two in the same slot resulting in a recreation of the previously broken item attached to the mouse-pointer (I still had 3 strikes left until it broke again).
I was able to repeat this as many times as I wanted, until I dragged another item than a Diamond Pickaxe into this slot.