gets/sets the open direction of the dropdown (either "up" or "down")
openDirection
Examples
$.w=150;
$.h=400;
const dropdown1 = $.makeDropdown($.w/2, 30, 100, [
"Option A",
"Option B",
"Option C"
]);
const dropdown2 = $.makeDropdown($.w/2, 80, 100, [
"Option X",
"Option Y",
"Option Z"
]);
function update() {
dropdown1.openDirection = "down";
dropdown2.openDirection = "up";
dropdown1.draw();
dropdown2.draw();
}