The Terrain Filters category display all terrain filters and filter groups as defined in the Terrain Filter Manager. The data can be in the active file or referenced files. The pop-up menu for a filter group contains a short-cut to the Terrain Filter Manager.
Another option on the pop-up menu is Properties, which vary depending on the selected item. For example, selecting Properties on a filter group displays the group information:
Note you can transverse the hierarchy within the Properties dialog. For example, selecting Obscure areas displays the General and Filter By information.
Editing can be done within the Properties by right-clicking for the pop-up menu.