View List & Preview Pane
The View List Pane displays a list of the views in the currently selected view category.
As you select each view in here, a preview image will appear in the Preview area in the lower half of the pane.
You can drag views out of this list into the View Composer to drop them into a view being edited. You can also drag a view over the View Categories Pane in order to re-categorize it. A normal drag will add it to the chosen category and a Shift+drag will move it to that category, thus removing it from all others.
Double-clicking a view in the list will open it into the View Composer for editing.