About start date and end date change event feature.

[AndriiAndreive]

This feature embeded in js file. Maybe someone needs to customize this string.
for example,

I think it should be work as option - selected date preview label format.
Thanks!

[kavvya97]

@dangrossman I have a pull request for this feature. I believe this is very useful feature to get the total number of selected days. could you please take a look
#2372