Expand / Collapse all windows sessions at once

[lbecque]

I have an enhancement suggestion that should be very easy to implement in the UI. When opening a session that has a large number of windows with many tabs in each (I have one with 28 windows, 200 tabs) it would be so great if there was one button to expand or collapse all the windows at once with a single click. Today, I have to click each window in the session while scrolling to click the next.

Also, it would be nice to save the display of each window as open or closed with the session each time it is used so you don't have to repeat the edit to quickly get to the windows you are using.