KyleMit's answer worked for me (thank you!), but I noticed that with select2 elements that allow for searching, trying to tab to the next element wouldn't work (tab order was effectively lost), so I added code to set focus back to the main select2 element when the dropdown is closing:
$(document).on('focus', '.select2', function (e) {
if (e.originalEvent) {
var s2element = $(this).siblings('select');
s2element.select2('open');
// Set focus back to select2 element on closing.
s2element.on('select2:closing', function (e) {
s2element.select2('focus');
});
}
});