What's the purpose of "back office espace" property

What's the purpose of "back office espace" property

  
If I look at the description in the help I see the following :
"... Back Office eSpace Whenever your application requires a back office, this is where you specify the eSpace that implements it..."

But what does it actually do ?
Is there a need to set this ?

Hi Joop,

As you have already discovered, that setting is used for the application switcher :).

Cheers,
Tiago Simões