How are the budget totals calculated

[John Haiducek]

When I go to edit the budget, there are a row of totals for "Income,"
"Expenses," "Transfers," and "Total" at the bottom of the screen. Can
someone explain how they are calculated? The behavior seems erratic.

Specifically, "Income" and "Transfers" get populated, but only after
putting seemingly magic combinations of values in just the right
sub-accounts under "Income." Similarly, "Expenses" never shows anything
but zeros for my main gnucash file, but with some finagling I managed to
get something to show up under "Expenses" after starting a new gnucash
XML file for testing purposes. Shouldn't these fields just show the
totals of their respective categories? Is this a bug or am I completely
misunderstanding what the fields are for?

John