I am sure that now it is better than before, but not sure if it is absolutely correct (despite the fact that I proposed it). Serbian Despotovina officially ceased to exist after 1459. and Ottoman conquest, but Vuk Grgurević was soon granted with title of despot (in exile, ok, but still despot) and gained control of almost all Syrmia within Kingdom of Hungary. There are sources that also name this territory as Serbian Despotovina, despite it was province that was part of Kingdom of Hungary, because it was ruled by despot who is Serbian, territory was mainly populated by Serbs and intentionally stimulating Serbs from Ottoman empire to settle there, free of tax, for making military frontier against Ottomans. There is no article about this despotovina, but I think that if Elsie wrote that: 
 "In 1485, at the death of her husband, Angelina went to Serbia where her son had become a despot," he could only mean this Serbian Despotovina within Kingdom of Hungary which need separate article. I will try to learn more about it.