Lend your screens to another computer
Decide which computers may show their photos on this computer's screens — allow once, always, or decline — and take a screen back at any time with Esc.
The Incoming pane shows what other computers are doing with this computer's screens. Another computer sharing the library can ask to show its photos on this computer's displays and main window; nothing is shown unless somebody here allows it.
Now
Each computer being lent to, since when, which screens it has and in which modes, and Stop, which closes its windows here and refuses it until it asks afresh. When nothing is lent, it says Nothing is lent.
Asking
A request waiting for an answer, which you can answer here as well as in the window that pops up: Decline, Always allow or Allow once. If it wants a screen another computer already has, it says so.
Always allowed
Computers that are lent to without asking, each with Forget — which also stops it, if it is lending right now.
Each also has a Kiosk tick. A kiosk computer takes the main window with no plain Esc: to get the window back, hold Esc, or press and hold on a touch screen, for three seconds. Kiosk pauses every time Portman2 starts, and whenever Esc is held on the main window, until you press Resume here.