xrandr moves panel away from screen border

[Achim Linder]

Hi,

Switching screen size with xrandr works fine as long as panel window
layer is set to "Top", but the panel is moved and stays in the middle of
the screen when switching back to the old screen size if the layer is
set to a different value. Gkrellm works as expected if I set it to
_NET_WM_WINDOW_TYPE_DOCK (with normal layer), the problem
with the panel seems to be that its window type (as reported by xprop)
is always _NET_WM_WINDOW_TYPE_NORMAL.

I had a look at the sources, but set_window_type_dock seems to be
the only relevant function and I haven't been able to find a place where
this function is actually used. Is there some configuration option
I haven't found yet, or is this a bug?

Linux, xfce4-rc4, default configuration.

Achim