save the cursor location for a named value
function (name, value, cursor, single) {
      if (value) {
        if (! htracr.ui.urls[name]) {
          ui.urls[name] = {};
        }
        if (single === true) {
          ui.urls[name][value] = cursor;
        } else {
          if (! ui.urls[name][value]) {
            ui.urls[name][value] = [];
          }
          ui.urls[name][value].push(cursor);
        }
      }
    }