Stealing focus - how to disable

I love Parallels and it's excellent handling and merging of OS X and Windows 8.

... well in most cases.

In one area I'm really annoyed. When I start Windows 8 Parallels takes focus from what ever task I'm doing after a while.
Ok, it's not a fatal error, just very very annoying. One never knows 'in how long' Parallels steals focus. One could just take both hands down and wait while Parallels reactivates / starts Windows 8.

Why not keep the operation in the background so I can get my work AND then switch to Windows 8 when I need to.
Hope someone can give a clue to how to amend this.

I know it's not a critical issue, like many of you guys and girls in here have, but ... it's very very annoying

Hope someone has the solution.

And M X-mas 2 all