this bug was reported on Ubuntu Launchpad as: 
https://bugs.launchpad.net/bugs/370100

Workrave is a gnome app which provides a system tray applet, which is my preferred mode of display. However, this applet is flexibly-sized but xfce4-panel (as of Jaunty) no longer allows applets to take up more than one icon's worth of space. As a result, the timers are basically unusable.

The workaround is to use the floating-window timer display instead, but I'd much rather have it integrated into my xfce panel instead.

Oddly enough, when I take a screenshot with 'import,' the timer ends up leaking out of its constrained window and clobbering a bunch of other stuff on the panel (and still being unusable), but on my actual screen it's constrained to a tiny icon-sized area.

ProblemType: Bug
Architecture: i386
DistroRelease: Ubuntu 9.04
NonfreeKernelModules: nvidia
Package: xfce4-panel 4.6.0-1ubuntu1
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: xfce4-panel
Uname: Linux 2.6.28-11-generic i686


I can confirm this issue still exists in Lucid Lynx. Using xfce4-xfapplet-plugin version 0.1.0-3ubuntu4, the applet still does not display correctly when placed between existing icons.