- Create 2 FPos (1 & 2)
- Create 3 customers:
  Customer A has no FPos
  Customer B has FPos 1
  Customer C has FPos 2
- Set-up the POS so that FPos 1 is the default FPos (FPos 2 is not
  accepted in the POS)

Issue 1
- Select Customer A

The FPos is set to blank, while one would expect to keep the default
FPos.

Issue 2
- Select Customer B
- Deselect Customer B

The FPos is set to blank, while one would expect to keep the default
FPos (as it was before selecting B).

Issue 3
- Select Customer C

The FPos is set to blank, while one would expect to keep the default
FPos since his FPos is not accepted.

opw-782855