I've recently installed Lubuntu 15.04, and everything is fine, except one (very annoying) little thing. My taskbar correctly shows all windows, displaying their title, but it doesn't update those titles as I browse different websites in Firefox, or go to different directories in PCManFM. So, the titles shown in the taskbar are those that the windows had when they were added to the list, they don't update anymore.
I've found that if I execute
titles are updated, but they don't change anymore. I've tried to create a new panel from scratch, and the wrong behaviour still appears.
It might seem a minor thing, but it's very annoying when you have three different windows labeled just "Mozilla Firefox" or "PcManFM".
Update: If I recreate the lxpanel profile (by using the template at
/usr/share/lxpanel/profile/Lubuntu/) it works again, but as soon as I customize the default panel and reboot, it stops working.
The following screenshot illustrates the problem: