xscreensaver fails to activate via "Preview" button or via "Blank after" setting

[Celejar <celejar@gmail.com>]

Hi,

I'm running Debian Sid with XFCE. Xscreensaver used to work, but a
number of months ago, it broke badly: it now fails to fails to activate
via the "Preview" button or (more importantly) via the "Blank after"
setting. It does still work via direct activation via
"xscreensaver-command" (and it is successfully activated by the system upon
suspend-to-ram).

I filed a bug about this, but subsequent to an interesting discussion
of the architecture of the software and its Debian packaging, the
maintainer closed the bug as unreproducible. The issues raised in the
bug discussion do not seem to apply to my system, but xscreensaver
nevertheless remains broken here. Can anyone help me figure this out?

-- 
Celejar