The dialog shows the views in a tree structure grouped by category. Views that are already visible are shown grayed out.
The Runner/Server Log in the Squish Tests group is not shown by default, but it can be useful when you need technical support.
The Squish IDE remembers which views are shown in each perspective between sessions, so you only have to add a view once for it to always be shown. Similarly, you only have to click the close button ( ) once to hide a view.