Also, it would be good if in the overall settings it is possible to choose browser bahaviour when opening new windows. To choose either "switching right away to newly opened window" or to "open new windows silently in the background".

Or other, even greater feature - predefine bookmarks that can be opened all with one click in separate instances / windows.

Where would I use it - at work we have quite bad radio coverage in the basement where the smoking room is located. It takes ages to load web pages there. It would be perfect to open all my faworite sites with one click just before I go to the smoking room where I like to read all the news and forums while resting and smoking...