the link you sent refers to QlikView - in which it indeed is possible to set a list box as having "always one selected value".
That possibility does not exist in Sense, as far as I know. Some of the extensions on Qlik Branch get somewhat closer, but still not perfect. But take a look at the extensions "Qlik Sense Option List" and "Dimension list (Cycle Group)".
While not perfect, they can maybe assist in achieving what you need.
Ideal would of course be if Qlik included this feature in Sense itself...