xsel unable to delete or replace selection

Binary package hint: xsel

xsel -d (or xsel --delete) is unable to delete selection, and xsel -i is unable to replace current selection.

To replicate:

Open text editor, or focus any text entry.
Write some text, then select it.
Open a terminal, then run xsel -d, or echo -n test|xsel -i

Expected result:

Text selection deleted, or replaced with "test"

Actual result:

No change to selection contents, text is deselected.

Versions:

Ubuntu 9.04

xsel 1.2.0-1