Another workaround (other than `killall gnome-panel` and/or `compiz --replace`) is:
1. Right-click on panel
2. Choose "Properties"
3. Toggle "Orientation" (e.g., if it's set to "Bottom", choose "Top" (let instant apply happen), and choose "Bottom" again).
I still have the same problem in Hardy.
Another workaround (other than `killall gnome-panel` and/or `compiz --replace`) is:
1. Right-click on panel
2. Choose "Properties"
3. Toggle "Orientation" (e.g., if it's set to "Bottom", choose "Top" (let instant apply happen), and choose "Bottom" again).