Wrap the row in a dynamic panel. Check the Panels “trigger Mouse Interactions” Checkbox.
Make sure, that the “isolate Selection Groups” Checkbox of the Repeater is checked off.
Add the dynamic panel(s) to a selection group.
OnClick the dynamic Panel setSelected(this).
Now add the requested styles to the items inside the dynamic panel inside the repeater item. If you want to have fancy stuff like appearance changes you can add widgets with normal -> opacity = 0, selected -> opacity = 100… or hover… or clicked… whatever you want.
the “trigger mouse interactions styles” of the dynamic panel is your friend!