#23 "Only new conversations" does not display notifies at all

>> https://bugs.launchpad.net/ubuntu/+source/pidgin-libnotify/+bug/823540

DistroRelease: Ubuntu 11.04
Package: pidgin-libnotify 0.14-4ubuntu4
ProcVersionSignature: Ubuntu 2.6.38-10.46-generic 2.6.38.7

"Close immediately" preference is active and the focus is elsewhere.
The message icon in the panel turns blue as expected, but no pop-up is visible.
Debug Window shows the following
When "only new conversations" is checked:
pidgin-libnotify: Conversation is NULL, setting up to check in idle
pidgin-libnotify: Unable to find buddy.

When both "only new conv" and "new messages" is checked:
pidgin-libnotify: Conversation is NULL, setting up to check in idle
pidgin-libnotify: Notify Message send has NULL Conversation, going idle
pidgin-libnotify: Unable to find buddy.
pidgin-libnotify: Conversation is not new 0xaa95808

When only "new messages" is checked: This works as expected:
pidgin-libnotify: Conversation is NULL, setting up to check in idle
pidgin-libnotify: Notify Message send has NULL Conversation, going idle
pidgin-libnotify: Unable to find buddy.
pidgin-libnotify: notify(), new: title: 'Lafiir2', body: 'test again', buddy: '(null)'
pidgin-libnotify: closed_cb(), notification: 0xaa98120