This is an issue that IT and I worked on for a couple of weeks that turned out to have a very simple cause and an easy solution, so I thought it might help others to post the experience here.
Environment: Dreamweaver CS3 running on a decent laptop that sits in a docking station at work with two monitors and just sits in my lap as a laptop when working from home over a Cisco AnyConnect VPN connection. I was trying to work from home for the first time, so it was not a case of something working before and then breaking--this issue was there all along. The rights to the laptop are far less than Admin. Using a strong wireless connection at home to a reliable cable ISP.
Symptoms: DW works fine at the office, but when I would take my laptop home and connect via VPN, the synchronize behavior was different. Whenever I would do a synchronize/get or a synchronize/put on a file or folder which I knew had been changed by my team-mate, the Preview window would not show up as expected, listing the files that would be changed. My team-mate did not have this issue when working from home. Interestingly, when I did a sync/get or sync/put on a folder or file that I knew had not changed, the behavior was normal and I'd see the usual pop-up saying there were no changes to sync, and asking if you want to see a list to sync manually.
Troubleshooting: We did all kinds of troubleshooting with IT, including rebuilding my Adobe profile (renaming various Adobe folders in the file system and in the Windows registry to be automatically rebuilt by the program), comparing all DW settings with those of my team-mate who had no such problems working from home, pinging this server and that, adding the FTP and HTTP servers to my HOSTS file, bypassing my wifi router at home and plugging straight into the cable modem, running DW as an admin, and chasing down error messages in the Event Log. My DW configuration mentioned something about firewall port 21, so I tried adding that to my router, hoping I was "opening" that port. Nothing seemed to change the behavior of the Preview list not showing up when expected.
Cause: Eventually I had an epiphany that turned out to be right. The problem was that I have two monitors at work, and at home I just use the laptop screen. Nothing was actually going wrong. But if I last had that Preview list window on the secondary screen at work, it would not appear on the laptop screen at home. And because the Preview list window does not get a Task Bar button, I couldn't tell that it was actually "appearing" in the nonexistent secondary screen. When the File Activity process is going, its progress indicator will have a Task Bar button, so even if it "appears" on the nonexistent screen, you can right-click the Task Bar button, select Move, and then use the arrow keys to walk that window into the visible space.
So apparently the main DW window has code that tells it to appear on the lone screen if it was last used on a secondary screen that is now unavailable, because it always launches in a visible space. The File Activity window does not have that code, but because it has a Task Bar button you can get around the issue and manually move it into the visible area. The Preview list has neither a Task Bar button nor the code that keeps it from showing up on a nonexistent screen. I'd say that qualifies as a bug, and perhaps it's not an issue in versions of DW that are newer than my CS3.
Solution: At work, before shutting down for the day, make sure that all the DW-related windows are dragged over to the primary screen, and those positions will be remembered the next time you run DW. Then when using the laptop by itself, everything will appear in the visible space.
Under Window >Workspace Layouts
You can create two different, well, workspace layouts with your palettes and panels where you like them. Then you switch back and forth when you have both monitors or just the laptop. I'm pretty sure it remembers where everything pops up too. You could test that pretty easily though.
Europe, Middle East and Africa