Whole day events cant be set to specific time in Calendar

Whole day events cant be set to specific time in Calendar

Hi,

There seems to be a problem with editing whole day events.
Whenever i create a event in Zoho CRM, i set it to whole day. When i try to update the time of the event in the calendar, the events stays a whole day event in CRM, and my update is reversed after refreshing the page.

How can i update a whole day event in the calendar into a event with a specific start and end date-time? 

hope to hear from you ,

Kind regards,
Yoeran