Hi Andrew!
While you can cycle through ETA styles by pressing F9 it would be nice to do something similar with the PPD calculation method (F7 or F10 are still unused ;-) ). This would also include an indicator in the main window for the currently shown calculation method.
However, one question is where to put this indicator. IMHO the status bar could be fine, although there isn't much room left. Something like "PPD style: <String>" would do it, where <String> comes from the already existing strings used in the Preferences dialog for setting the calculation method. (Alternative indicator names: "PPD calculation", "PPD method")
In case of an implementation of the suggested function you could clean up the Preferences dialog by removing the entry "Calculate PPD based on" from the tab "Monitoring". IMO it would not make any sense to leave it there. (This actually also applies to the setting "Display dates as".)
Have a nice day
Mark