Hello chrisd,
In the version 1.3 Pair preselection can be:
- disabled (all preselection options unchecked), = equals to Disabled Preselection in 1.2.
- generic, = equals to Generic preselection in 1.2.
- reference,
- reference + generic. = equals to Reference preselection in 1.2.
The latter two options are available only in PhotoScan Professional.