addChild does not add sprite to front?

Simply put, I am adding a sprite to the stage on the event of a button being pressed. The problem is that it hides behind my other sprite that is attached to the stage on runtime.

I have also tried messing around with addChildAt() but with no success.

The other sprite that is attached on runtime is added to the stage through a class. Could the sprite within the class be disrupting the layering/z order?

Don’t know too much about flash and havn’t used it for a while so any help would be great.