how to protect anonymity of users using menu / bookmarks bars?
I am concerned that users adding a menu bar or a bookmarks bar to their tor browser may be reporting smaller and trackable window heights to websites. I am not sure if this is the case, but I suspect so.
I'd make the case that reporting a set window size to websites regardless of what the actual Tor window is is the safest option. An extra button between minimize and maximize could resize the window to the expected size when needed.
Another reason to consider this option is that well-meaning users trying to move the window sometimes wind up resizing it without intent, or in trying to resize it dispell the warning and work in another size window. This is difficult to avoid with trackpads, which are prone to drag-and-drop errors. And then the user must choose between restarting the browser and losing work or potentially not even realise it and continue working in a compromised manner.