Date/Time Default

I'm currently using IGOR Pro Version 8 to graph about a months worth of ambient air quality data. My goal is to separate the data based on a specific Time/Date period (i.e over the course of a few days). I've set both the Mode to "Date/Time" and the "Manual Range Settings" to Date/Time, yet when I try to make the graph, the Manual Range Settings defaults back to Date and time is no longer displayed in the graph. What is also perplexing is that sometimes the Time will show along with the date, but in other cases it does not. Is there a way to stop the Manual Range Settings to stop defaulting back to "Date" only? 


I suspect that there is a maximum date range for displaying the time. If the axis range is greater than that minimum, Igor suppresses the time to avoid clutter.

For example, this does not display the time:

Make/O test = sin(x/8)
SetScale/P x, date2secs(2019, 10, 17), 3600, "dat", test
Display test

But after executing this, the time is displayed:

SetAxis bottom Date2Secs(2019,10,17), Date2Secs(2019,10,19)

Complex code is involved in the decision to display time or not. It looks like it displays time if the number of days displayed is less than the number of tick marks. Consequently, in this example, this command makes the time appear:

ModifyGraph nticks(bottom)=6

and this command makes the time go away again:

ModifyGraph nticks(bottom)=5

The nticks keyword corresponds to the Approximately text box in the Auto/Man Ticks tab of the Modify Axis dialog.

If that does not explain what you are seeing then please post a simplified experiment or commands like the ones above that illustrate the problem.