First-In-First-Out (FIFO)
When NETTING the open positions, Saxo uses FIFO rules, which means the first position you open is the first position to be closed.
How do I see if there are any related orders on my square position?
The following icon is indicating, that position has a related order: 
.
In below example (picture 1) USDJPY is marked as Square, but it has a Stop order at 111.26 on a Short position. In order to have USDJPY long and short positions net out and removed, you need to cancel the order, by going to Orders section (picture 2).
Picture 1
Picture 2
How do I see, if positions were opened from different accounts?
Account number is visible in Positions list. If you do not have it displayed, please enable, by going to Settings for editing a layout 
in the right corner.
In below example Facebook CFD positions were opened from different accounts. A long position is opened from TRIAL_2211568 and a short position is opened from TRIAL_2211568U. In order to net out two opposite positions, it must be allocated to the same account.
If you request to do so, please read How do I transfer positions between my sub-accounts?
