Dear Adamchuk Nicolay,
Is this a Revit API issue, or an end user question?
Are you doing anything programmatically, or just using the standard Revit user interface?
If this is an end user issue, I think the normal product support may be better able to help you.
You should try one of the non-API Revit product support discussion forums instead for that:
I hope this clarifies.
Thank you for your understanding.
That said, this does indeed sound like a problem to me that needs to be looked at.
If so, a reproducible case will certainly help product support analyse the issue in more depth:
http://thebuildingcoder.typepad.com/blog/about-the-author.html#1b
Best regards,
Jeremy