When using a piecewise linear (PWL) voltage source, KiCad lets you enter the (time,value) points for transient analysis, however the points are sorted in order they are entered. If they are not entered in chronological order, ngspice give error "voltage source V1 has non-increasing PW time points. Points are not editable once entered. If you want to change a point you have to remove the point and add a replacement, however this results in the point added to the end of the list which generates the above error. The only fix is to delete all the points and re-enter them 1 by 1 in order. It seems like an easy fix to have add point or save force a sort on the points, or initiate a sort by clicking the time column header. Has anyone found an easier work around for this issue?
As far as I know, there is no built-in feature in KiCad to sort the PWL points, there is a workaround you can use to sort them manually.