UV maps and SHape keys + edge slide - UV maps stretches even with UV correct ON

When we use shape keys and edge slide how can we key the current uv map layout. When we dont use shape keys and use edge slide the uv maps stays intact. But when you have 1 or more shape keys the uv maps begins to stretch and isnt correct no more.

Is there a way to do this without moving the uv map?

OSX 10.11.6
BLender 2.78

BUmped into the issue again now. For now i made a new combined shape cause it will not be animated. But im curious how can we keep a UV unwrap using say the last shape key added?