Problem linking erased group

Hi all!

I’ve a problem and I’m not sure if it’s a bug or something I’m doing wrong…

I linked one group to a file and then erased it. When I try to link it another time, it does nothing.

I’ve tied the same test with other files and the result is always the same: you can’t link groups you have previously erased.

Does anybody have the same problem?
I’m using the last Blender stable 262 64 bits for Windows 7.

Thanks all!

Append on deleted previously linked/deleted group also doesn’t work. Bug?

EDIT
Not a bug. Best answer probably is this one

“You can not actually delete anything in Blender, only “unlink” it from an object or the scene. It remains in memory and still available for re-linking until you close the BLEND documents. The only way to actually remove the objects from the memory space is to unlink them, do a file save, close Blender then re-open the BLEND file.”