The showcase dialog can be configured in several ways.
Dialog layout: The dialog can either have a horizontal or vertical layout. In a vertical layout, the main pane is at the top of the dialog.
Fields to use in my channels: When you select a channel from the showcase listings and press OK, that showcase's information is retrieved for your current channel that you are configuring. This checkbox toggles whether you wish to retrieve all possible fields (name, url, maxdepth, etc) or just the name and URL only.
Choose fields to display in details pane...: This allows you to choose what fields appear in the details pane, when a channel is selected.
Power user tip: If a channel does not have an entry for a certain field, then that empty field will not be displayed in the details pane.
Include images in channel previews: If checked, images will be downloaded and included in the channel previews. Turning the images off makes previews be displayed faster. This feature is not yet implemented