Editor User levels duplicator (backup)

[Moved from "Editor" thread].
By "level duplicator" I mean feature that I can copy level made in editor in any state. For example: I open new level, put stone wall, exit editing, name level "stone wall", duplicate it, so there will be 2 same card, change name of a copy to "stone wall 2", edit copied card. I can modify copy, but I have backup of level start position in "stone wall" card. I hope it's writed clearly.

 

[FR]=[Feature Request]. This type of shortage is common used in forums topics. I changed topic so no more misunderstanding.