Q:

highlight selected item in flowlayoutpanel

how do i highlight the selected item (in my case, a custom user control) in a flowlayoutpanel

A:

FlowLayoutPanel is purely for layout - it has no concept of a "selected item".  You might be able to add some logic to your UserControl which changes its colour when it receives focus (and changes back when it loses focus) but that would be independent of the layout control that's hosting it.