I think they need a up/down button that will cycle through your retainers without having to go through the menus again.

For example, I have 3 retainers:
A
B
C

If I open A's items, and then click the down button, we will switch to B's items. Clicking down again will go to C's items. That will allow us to quickly go through all the retainers and manage them without the crazy amount of clicking.