@pointbob Think first.
Open your damn pages in several windows once! When you do it, use them, then close first (main, parent) Opera window with Ctrl+Q buttons. All your "pages" (>>windows<< per favore, not pages) will close one after another. Go to sleep. Get back to work. Then click your Opera icon where it is. All your Opera windows closed earlier will open again. No magic, Opera helps those who helps Opera thinking how to use it.
Mr Point Bob.