When running pypanel under blackbox 0.70.0 there are no tasks. Puting in a few prints the problem seems to be in setState(). The line:

task.state = task.obj.get_full_property(self._STATE, Xatom.ATOM).value

Raises an attribute error on 'value' because the return object from get_full_property() is always None.

According to the blackbox 0.70 release notes _NET_WM_STATE is supported (ie. self._STATE), though not all the _NET_WM_STATE_* atoms are supported. Here's the list from the release notes:

_NET_WM_STATE: supported
_NET_WM_STATE_MODAL: supported
_NET_WM_STATE_STICKY: NOT supported
_NET_WM_STATE_MAXIMIZED_VERT: supported
_NET_WM_STATE_MAXIMIZED_HORZ: supported
_NET_WM_STATE_SHADED: supported
_NET_WM_STATE_SKIP_TASKBAR: NOT supported
_NET_WM_STATE_SKIP_PAGER: NOT supported
_NET_WM_STATE_HIDDEN: supported
_NET_WM_STATE_FULLSCREEN: supported
_NET_WM_STATE_ABOVE: supported
_NET_WM_STATE_BELOW: supported

Is this the problem or is there another issue at work here? 

Thanks.

It's part of the problem, I fall back to querying WM_STATE which works ok for BlackBox.  This is fixed in v2.3 which should be available in a few days.

Thanks for the info. I'll look forward to 2.3.

Out of curiousity, what's the other part of the problem?

Sorry, I should have phrased it better - the 1st part of the problem was what you mentioned in your first post, _NET_WM_STATE was returning None.  The 2nd part of the problem was that I wasn't querying WM_STATE when that happened. 

Now, both properties are queried and if WM_STATE fails then there's a good chance the application was destroyed.