Hello Martin,

when the grid is in display mode you cannot toggle the checkbox. When the row enters edit mode, then you can check the checkbox for that row.

Clicking the checkbox multiple time is expected behavior but there is some workaround for this, you can add the following code in the sample.

$("#grid").on({
                "click": function (evt) {
                    var grid = $("#grid"), checkbox = $(evt.target).closest("[role='checkbox']"),
                        val = checkbox.attr("aria-checked") === "true",
                        rowId = checkbox.closest("tr").data("id");
                    if (!grid.igGridUpdating("isEditing") && checkbox.length) {
                        grid.igGridUpdating("setCellValue", rowId, "MakeFlag", !val);
                    }
                }
            }, "span[role='checkbox']");