Really Need Silverlight Editor

I can't edit big scale maps, it always freezes or crashes even though I have a good pc. It usually takes like 20 minutes to save the map. And it has a very high chance to bug your map and when it happens, you have another undeletable and uneditable map. I got a big junkyard of them now. (it's probably wasting space uselessly in the servers)

I didn't have any problem like this in SL editor. It's maybe possible to do this.

https://atwar-game.com/play/

That doesn't let me clone or make a new map.
I only get a corrupted map when I save a cloned World Map with another background image. There must be a way to do it...

I'm only doing this for the World 2.0 contest. I don't personally like to make big scale maps that much.