I will write this stuff AFTER I have working version and no major architectural changes. In the meantime the only thing here are meaningless mumbles.

How does rendering of map works?

For entity like this:
TLEntity<-TLRenderableUTAgent<-ISubGLRenderer<-map

When entity is supposed tobe added, in TLMapGLPanel updateEntities is called and new renderer is created and added to GLRenderCollection.

How is it all connected

Graph here, ASCII art for now

    
TLMapGLPanel
     ||
     \/
GLRendererCollection =======================================================
        ||                    ||                     ||                    ||
        ||                    ||                     ||                    ||
UTAgentSubGLRenderer   UTAgentSubGLRenderer   UTAgentSubGLRenderer   UTAgentSubGLRenderer
        ||                    ||                     ||                    ||
        \/                    \/                     \/                    \/
 TLRenderableUTAgent   TLRenderableUTAgent TLRenderableUTAgent   TLRenderableUTAgent
        ||                    ||                     ||                    ||
        \/                    \/                     \/                    \/
    TLEntity               TLEntity               TLEntity               TLEntity

When is map re-rendered?

When database emits onChangedCurrentTime(), one of listeners is TLMapGLPanel. It updates map entities and other stuff and calls display which rerenders all GLEventListeners of the panel.