Remember last 'position/size' or 'always center' child windows❔

[petermad]

I don't get why the BTM has an option to save its position but the normal background transfer windows do not?

Well try with a freshly started TC to start several copy operations after each other (must be long enough to be able to start each one before the previous operation ends) and send them to the background - notice that each background copy window is placed next to the previously opened one. If you could save the position of the window, they would all be on top of each other.