When adding a new link or folder by clicking the Link Current File... or *Link Current Folder... buttons, the [Files] and [Folder] icons will not show a -/+ expansion icon next to them if there are additional groups inside them. You can still double-click them, but it's not clear there may be subgroups.
On the other hand, if you double-click on them and you have groups with subgroups, those will have a -/+ expansion icon to indicate they have subgroups.
When adding a new link or folder by clicking the Link Current File... or *Link Current Folder... buttons, the [Files] and [Folder] icons will not show a -/+ expansion icon next to them if there are additional groups inside them. You can still double-click them, but it's not clear there may be subgroups.
On the other hand, if you double-click on them and you have groups with subgroups, those will have a -/+ expansion icon to indicate they have subgroups.