Hi Sander,
If you change any readout settings, they should be remembered across PI Core sessions. Otherwise we have a bug, but I've just tested this on all platforms and it works as expected.
To modify readout settings, you can use:
- The "little blue arrow" on the Readout tool bar (bottom)
- The ReadoutOptions tool (Edit > Readout Options, or Process Explorer > Global > ReadoutOptions)
By the way, I have discovered that the "Preview center hairlines" option does not work on the ReadoutOptions tool (it is ignored and not loaded when the "Load Current" button is clicked). This is a little bug that I'll fix. This options does work on the "blue arrow" menu though.