In my previous post I mentioned degraded performance when using Treectrl's own tag mechanism instead of keeping an external array. Since the roster widget is the most time critical one, perhaps next to the disco tree, I had worries about this.
Sometimes it doesn't pay off to be smart and write the best possible code. Good code can be slow and bad code can be fast.
The Treectrl widget which is a core part of the Coccinella came with a 2.2 release a couple of months ago, and this included support for the much awaited tags. Each item can have a list of more or less arbitrary tags instead of being referenced with just a number, which may change if items are recreated. Previously I just kept an array that mapped tag to item number.
If you didn't know PEP means Personal Event Publishing (www.xmpp.org/extensions/xep-0163.html) and is a kind of shortcut into a PubSub (Publish and Subscribe) that has been discussed since last summer, I think. At that time Magnus Henoch made a PEP patch to ejabberd but due to various circumstances I did only preliminary tests. In addition the patch didn't had the key caps/notify feature which didn't make it useful.