Filling problem

[BuilderNOT]

I have recently had a wall replastered which use to be an opening and it cracked very slightly down one side only so I bought some hairline crack filler and now it's cracked round the edge of the filler and also if the light isn't on in that room you can see the whole strip of filler, where did I go wrong?

Thanks

 

[dcdec]

Could be that the plaster is poorly bonded or applied to thinly over a joint thats flexing or that you painted before it was properly dried out. The other problem is known as flashing, to avoid this you need to apply thinned emulsion to the filler once its dry and rubbed down