>I think, I have to add a label, which would indicate, that this is a new cloned record and would be visible untill save or revert buttons would be pressed.

This would be distracting and annoying for data entry, IMO.

>Threfore my question: how can I create a flashing effect for this label by simplest way? I'm not sure, that I want to use timer for this...

The simplest way would be a timer, why wouldn't you want to use it?