- Moving tabs between windows and sessions is in the todo list, but I haven't figured out an intuitive way to move tabs over windows or sessions that are not visible on the same display pane.

- The popup window size is made as big as Firefox allows. Moving to full page in a new tab is an option but it will require lots of rework, and also the UI will open slower, breaking the user's flow. I'll put it in the todo list but it's a lower priority item.

- There's an implicit privacy contract that the private window's data (including the tab urls) are not saved after closing. I feel strongly about it and private window data are not going to be saved. Sorry.

- Actually I don't know how to do it. I couldn't find any monitor-related information Firefox provides to extension.

Thanks for the feedback.