What does the option "Background Query" do (option in Pivot Tables for external data)

I have a pivot table pulling data from Oracle. I noticed the "Background Query" option but doesn't seem to do anything. Anyone have a clue what it does?

Kind of, basically says what I thought it does but it doesn't seem to work like that. When I refresh it still locks up the workbook.

Have two other questions:

1) Does the "refresh every X minutes" work when the workbook is closed or only activated once you reopen the book? I assume only when open which sucks.

2) I have never fully understood how to get the preserve formatting to work right. I always have to turn it off, make changes, turn it back on, refresh (which loses the changes), then make the changes again, then save. from then it seems to stick but not sure why I have to go through the first few steps