Good point: That was the original plan but I have a long list of 12 entries and adding the HTML to the DOM for each of these entries at once leads to delays. You can literally count to two until the page is updated.
The approach I am taking now is create several tags, assign a view-Model only holding the bool if the button to show details was clicked. In addition the "original" data structure. Here the part covering the details for the selected element is passed down from the previous tag.
Probably kind of wrong but at least it keeps the data and the view config separated.