Investigate the possibility of plotting multiple data at the same time on different windows

Hi @GiulioRomualdi @paolo-viceconte @isorrentino, I am opening this issue just for brainstorming. I was thinking that it might be useful to have the possibility to display multiple plots at once, especially when the y range is very different.

I was trying to understand myself first if it could be feasible, and I found https://stackoverflow.com/questions/45765653/add-multiple-docked-widgets. Not sure if it is actually possible though. For example, if I understood correctly, the list of variables is in sync with the currently displayed plot. I don't know how this could scale in case of multiple windows. Maybe using the focus (https://stackoverflow.com/questions/19511051/how-to-get-active-qdockwidget-in-qqmainwindow)?

What do you think?