When using the TDSHT3+ why is my histogram box is not showing any Pk-Pk jitter value?

When using the TDSHT3+ why is my histogram box is not showing any Pk-Pk jitter value?

The empty pk-pk histogram or -- in the pk-pk histogram value implies the absence of data points in the histogram window (Box). Increase the record length value and run the test again or draw a bigger histogram window to find the Pk-Pk jitter value.