Topic on Talk:Modding Tutorials/ThingComp

PostDraw will not be called unless the parent of the comp has a drawerType of MapMeshAndRealTime, much like how CompTick won't fire unless the parent has a tickerType of Normal

I have not investigated further, but it seems the few implementations I found of PostDraw in the vanilla code all tie to XML objects with <drawerType>MapMeshAndRealTime</drawerType>. My own mods which implement PostDraw were broken in 1.3 which is where I learned PostDraw was no longer being called.