collapsible: when not set, gives a link in the menu but without submenu's; they do appeatr on this (_index) page.
filename must be _index.md or .rst etc - if just index, it will not work to give unfolding menu.
rst subtitle is set
Agroforestry addresses a wide range of needs at the household/farm level. It has potential for sustainable resource management. Agroforestry (AF) programs must be economically attractive to farmers and sponsors, and fit the context if they are to be successful.