LINQPad 9 Bug - MultiSelectListBox - set SelectBox.SelectedIndexes doesn't work

In LINQPad9, methods for selecting multiple options in SelectBox with MultiSelectListBox kind doesn't works.

The code delays for a few seconds on the line with calling methods sbx.SelectedIndexes or sbx.SelectedOptions and the options are not set.
(Sometimes at this line the debugger hangs)

The code for reproduce bug:

string[] opts = Enumerable.Range(0, 32)
    .Select(e => Math.Pow(2, e).ToString())
    .ToArray();

int[] selIdxs = new[] { 3, 5, 6 };
object[] selOpts = new object[] { "4", "16", "32" };

SelectBox sbx = new SelectBox(opts);
sbx.Kind = SelectBoxKind.MultiSelectListBox;

sbx.SelectedIndexes = selIdxs;
//sbx.SelectedOptions = selOpts;

sbx.Dump();