Strange editor behaviour.

I'm found my custom editor's work a little bit strange.

I'v created ny own FileEditorProvider, and it works good. When I open a file in project idea opens my editor.
But if I left some unclosed files, at next start, Idea won't create custom editor, it uses default one.

If I close this file, and reopen it, I will see custom editor again.

Can this happen due because of some time lag between Idea startup and file opening, and plugin initializaton?
Because I'v noticed, during "Indexing", I can open only default editor. and when It done - reopening file shows custom editor.
How can I manage It, may be programmatically reopen all editors, after provider registering?  If so, how determine corect timing, correct moment to do so?

I would be grateful for any idea.