The event creation page shouldn't close if I switch to another app and back
If I try to add an event, then switch to another app (to check the address of the place, get email of the attendee, etc.), page for the event creation is closing.
Which means I need to know and remember everything when I enter the creation page. That's not very use friendly
It is the case, unless you use widget to quickly add events. In such case the app will not be opened therefore you cannot go back to it as it is not in the recent apps. What happens when your create an event from the widget is the input mask being opened to enable the introduction of the event details. No data is saved in such case until the 'save' button is clicked.