To see two pages side by side, formerly you had to resize each window & bugger-up all page views. I do it all the time, but find easier mentally to have different browsers, speed is king when searching, say, satellite maps. I do it with browser & spreadsheet. If you work from one laptop in the field, this is all you had.
But there are times when having a split tab is easier. Horses for courses. Strokes for folks.
I produce maps with coloured pins and pop-ups that have hyperlinks to other resources. Offer them to people who say "thanks BUT can you filter the geographic info in a spreadsheet"!!. (for targets 1 square metre) & my map uses GPS "you are here". Some folks are data oriented some are visual. Never the twain!