Short version :
How can we ask an editor to do some stuff, when it is created, just
before it gives the control back to the user.
When the user opens a java file in an editor, IDEA will
1/ load the file in some way
3/ add all the persisted fold regions (methods, fold selection, etc..)
5/ give the control back to the user.
I need to do some action after (3), and before (5)
The /EditorFactoryListener/ only allow us to place some action before (3).
That's too early, as IDEA hasn't created the FoldRegions yet.
How can we "inject" some action, between (3) and (5).