if you reopen the tranding menu, the textfield is empty, but the last search is applied
expected: text shows (active) search string
fix:
in scripts/gui.lua in function Trades_menu:open(player)
-- after
self:create_list_rows(trades_list, global.cities, search_term, filter, player)
-- add
self:update_search_text(player, search_term, filter)
