Sorry that I got busy and didn't follow up on this thread. I saw dmg IRL today and he reminded me I hadn't replied.
I've attached my xwininfo from my xfce-panel, which does has Window-Type Doc set. Note again that this DTRT with sawfish 1.5.3-2.1+b1 as packaged with wheezy (i.e., panel has no decoration), but I get the window decoration when I run the version from Git master. dmg, are you running from Git master branch?
xfce-panel.xwininfo
Description: Binary data
-- -- bkuhn
