Property displayers don't work in the object editor for objects that have just been added

To reproduce:

• Download 5.0RC1 standalone zip and start it
• Create a page containing one class with 2 props: one of type date and one of type list of users.
• Create another page and go in the object editor
• Add an object of the class you've just created

Notice that the 2 properties of the added object don't have the date picker and the user picker (respectively).

Refresh the page and notice that the pickers are working.