Are you sure the problem only occurs when Dexpot is running?

I use a laptop with an external monitor to use two desktops. Sometimes my monitor bugs out and the laptop thinks it's not connected anymore so it drops down to a single desktop. When this happens, any applications that were on the secondary desktop do show up on the primary desktop, but the taskbar icons for those windows are gone. This happens in the latest 1.5 release as well as the latest build of the 1.6 beta. I have to either restart all the programs or restart windows to get the icons back.

Again, Windows 7 ultimate 32 bit.