winprop.target and nested workspace

Hi,

I have saved the following layout into my session:

groupws1 - frame1 ------groupcw1 -- window1
                                     |_ groupws2 -- frame2 -- groupcw2
-- window2

I also defined winprops with target = frame1 for app1 and target =
frame2 for app2.

The point is to have a workspace (groupws1) with a frame (frame1) than
contains a window (window1) for app1 and a nested workspace (groupws2)
with a frame (frame2) that contains a window (window2) for app2. This
is how I see it when I save the session and this is how I want to see
it when ion starts up again.

But when I restart ion both app1 and app2 end up managed by the tiling
of frame2. In terms of what I see they're siblings at the nested ws
level (groupws2). If I manually attach app1 to frame1 the layout is in
fact rearranged as I desire, so it seems that win.target = frame has a
different semantic than frame:attach(win).

Is this a bug or am I missing something? How can I achieve the desired result?

Sorry for the plethora of questions, I can't wait to master ion :).

Regards
-Carlos