When galleries are sent directly to clients without a secure link, the “navigation from sub-galleries and vice versa” are available. The function in the settings of the original gallery controls whether their sub galleries are visible. If this function is activated, the client can view all sub-galleries from an original gallery and pull them up with a click. Of course, this also means that they have to be able to navigate up to the parent gallery again from a lower gallery. To put it simply: a staircase that you can walk down from the ground floor into the basement must also be able to walk up again. If you now want the client to be able to navigate from there, you must deactivate the function “Navigation to sub-galleries and vice versa” in the parent gallery. Thus no one in the parent gallery can see the sub-galleries – and vice versa.
Update: These settings are still effective if e.g. only one single sub-gallery is released by a client login and the client came directly into the sub-gallery. This point and a few less important points are the reason why client logins are currently still “BETA”. In the future, we will change this function so that every single gallery has to be explicitly added to a client login, even if it is a sub-gallery. Also, the permission settings of top galleries will then be ignored at client logins. This will make it easier to understand.