1. Right click the taskbar, choose properties, and uncheck the checkbox that
says "Keep task bar on top of other windows".
2. Click Apply
3. Check the checkbox again.
4. Click Apply again.
This will temporarily make the system work right again, but you will have to
repeat these steps if it happens in the future.
Update: Neosmart has created a small application that will fix this problem.
The only thing is that the application will need to be running all the time,
but if you have this problem often enough, you won't care.