If you still interested..
Here how I recreate the problem.
1. Start with apply Acrylic 7. or any other theme. But Acrylic 7 usually works for me.
2. Open 3-4 windows explorer. (make sure the taskbar button option are set at always combine, hide labels.)
3. Apply Arsenic. Sometimes you need to apply it couple of time to actually see it but immediately after the please wait animation disappear. You will see it. I tried with your solution and it still happened.