I have set render layers, combined in compositor. Post processing is checked for compositing. the rendering rendered all 3 layers but the final outcome is only one fo those layers. the viewer and the final render is different.
(something that is weird: i tried both cpu and gpu to render, previously does not have this problem but recently when i render after the 1st layer, the img of the first layer is still visible while rendering the second layer, only "overwrite" when the boxes render the portion, i wonder if it is a bug...)