The layers of the geographic data are grouped according to topics which can be selected according to a tree.
Within a topic the layers are arranged in two hierarchical levels. The layers of level 2 can be selected individually, whereas a selection of a layer of level 1 will include all sub-layers.
With "open" and "close" the topic tree can be opened and/or closed.

If there has been a change in the selected layers, you must click on "updating" in the tool bar above the map in order to modify the map.