The Problem: When user remove 4rt fullday event, header only shows two
events and not shows 3rd fullday event
Because, we check and set visibility of event that user wants to remove
from calendar, before remove event from event list which causes 3rd
event unvisible.
Fix that with check and set visibility of event after remove event
from event list, then visibilties and overflow corretly calculated
https://bugzilla.gnome.org/show_bug.cgi?id=777423
