Wish there was an option to have deleted events immediately be removed from showing in the calendar. Currently, it doesn't disappear until I sync with my phone. However, I only do that once per week and in the meantime it is very distracting to continue seeing events I've already dealt with continue to display. Surely it's possible for the app to remember the deletion in the background and not have to still show the deleted event in the calendar until the next sync.
The MPE is a tool to synchronize the phone with the computer, not a calendar.
So if you delete an event you have to sync.
If you're looking for a calendar to work with on your computer you should consider using Outlook.