Hello,

Unfortunately, the Custom table repeater uses QueryRepeater control which does not provide selected item transformation. It is caused by the fact that query repeater is not implicitly displaying documents from Kentico CMS.

You will need to develop this functionality by yourself. Basically you can inspire by standard CMSRepeater. At first, you could generate list of items using (standard) transformation. Then, you could create links so that they point to same page with some query string with information (e.g. ID) about selected item. Then in the code-behind you could add some code that would change the transformation to some other (that would represent "selected item transformation") when there is information about a selected item presented in query string. You may also need to change the query (or use where condition) in this case, so it displays only selected item.

Best regards,
Michal Legen