This applet stores the junk-mail list, content-list and the subject-list files locally. The applet uses these files to build the junk mail rules. When a user changes from there desktop to laptop, the settings files are not being transferred. This causes the applet to re-build the rules again (deleting any previous rules), using the settings files that exist on the notebook at the time the applet is executed.
The only work around to this problem currently is to manually (or otherwise) copy the appropriate files from the desktop-notebook-desktop – not particularly elegant. We do have plans to possibly upgrade this currently free applet to use another system to save settings that travels with the account. I don’t have any delivery dates for this at the moment.