This window is used to select the domain used for browsing.
Double-click a domain in the list to select it.
Add another domain to the list of selected domains. If the added domain is already in the list then its credentials will be changed to those entered.
Edit the domain that is currently selected in the list.
Remove the selected domain(s) from the list if they are no longer needed. There must always be at least one domain in the list, so you cannot remove the last one.