Enable or disable the "mandatory" property of fields in an AEM (ExtJS) dialog.

SetMandatoryPropertyInAemDialog.js

// Can be called in (for example) a dialog by appending to a listener like "selectionchanged" (for a checkbox).
function (checkbox) { switchMandatoryFields(checkbox); }

// Enables or disables the "mandatory" property of the defined fields.
switchMandatoryFields = function(checkbox) {
    "use strict";
    var checkboxIsChecked = checkbox.optionItems.items[0].checked,
        parentPanel = checkbox.findParentByType("tabpanel"),
        firstTextfield = parentPanel.find("name", "./nameOfFirstTextfield")[0],
        secondTextfield = parentPanel.find("name", "./nameOfSecondTextfield")[0];
    if (checkboxIsChecked) {
        if (firstTextfield !== null) {
            firstTextfield.allowBlank = false;
        }
        if (secondTextfield !== null) {
            secondTextfield.allowBlank = false;
        }
    } else {
        if (firstTextfield !== null) {
            firstTextfield.allowBlank = true;
        }
        if (secondTextfield !== null) {
            secondTextfield.allowBlank = true;
        }
    }
};