Compositor is actually working, but the result is not showing in the UV image editor. I cannot share the blend file due to some reason.
I have two different scenes with two different cameras and different composition. Here is how I have setup the nodes in the compositor.
I have used two different render layers connected to a different composite node in the end (donated by red box). The compositor option is also checked in the properties. The result previews just fine for both scenes in the compositor, but nothing ever happens in the UV Image editor. I have tried restarting blender. Nothing is working here. I have rendered it many times, and it’s just not working.