Right click panel, click "New Panel"
Right click the new panel, choose "Properties", and uncheck "Expand"
You should be able to drag it to the other monitor.
Open the panel's properties, and check "Expand" again. You may also have to choose to place it on the bottom edge of the screen.
Right click the new blank panel, and click "Add to Panel"
Choose "Window List" and click "Add". Your programs will show up in a list on the screen they are visible on.