1.My script is wrong,"if (widget == null)" should be "if (widget != null)".

2.The wrong script worked well on ngui3.7.4 but can't work on ngui3.8.0,both Unity5.
3.I change my fault and test again on ngui3.8.0,find it can't work very well still,mesh and UIWidget depth only decided by position,particle and UIWidget depth decided by position and renderQueue.Maybe is Unity standard shader's business.