I'm seeing an annoying problem when multi-boxing and wonder if anyone here knows what's going on.

My setup is:
- Main char running on main PC, windowed + maximised in WoW video options (1920x1200)
- Four clones running on second PC, each running under WoW Maximizer to use one quarter of the screen (4 x 960x600)
- Octopus used to broadcast mouse and keyboard

The problem is that the fourth clone on the second machine, displayed bottom-right, often freezes until I move the mouse over the window. This never happens with any of the other three windows.
Also, the character in this window also seems to lag a bit more than the others. It's always hanging back a bit when the four clones are following my main.
Another weird thing is that if I hit 'B' to open all my bags, the main and first three clones will open bags, but the fourth clone won't. If I hit 'B' again, they all close bags but the fourth clone then opens it's bags.

Can anyone suggest what the problem is and how to fix it?

Cheers.