Forms Tab order on serenity form

For input controls, like textbox, textarea...

this.form.FirstName.element.attr("tabindex", 1);
this.form.LastName.element.attr("tabindex", 2);
this.form.Email.element.attr("tabindex", 3);

If control is dropdown which implemented by select2 library, try this:

this.setTabIndexSelect2(this.form.SupplierId.element, 4);


private setTabIndexSelect2(element: JQuery, tabIndex: number) {
   element.prev("div.select2-container").find("input").attr("tabindex", tabIndex);
}

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Original issue: https://github.com/volkanceylan/Serenity/issues/3935