The UISlicedSprite are not be used in the version of NGUI 2.51 ?
I find the UISliceSprite are error ,eg :
void SlicedFill (BetterList<Vector3> verts, BetterList<Vector2> uvs, BetterList<Color32> cols)
{
Color colF = color;
colF.a *= mPanel.alpha;
Color32 col = atlas.premultipliedAlpha ? NGUITools.ApplyPMA(colF) : colF;
}
The variable "mPanel" is null !!!!!