Offline maps

Q: Is there a tool in UgCS that shows all areas that you have downloaded as an offline map, similar to custom elevation data?

There is no exact indicator showing where the maps have been pre-cached and where they have not - when switching to offline places with un-cached maps will be blank. For offline work, it is recommended to use your own GeoTIFF or pre-cached map data.
Detailed information on how to set maximum cache size is described in the UgCS desktop user manual section ''Custom maps'' and ''[Offline maps]

There is also an option to use your own map server from which UgCS takes map tiles.