Alice Keeler is the Google Classroom guru. Her website is truly the one-stop shop for all things Google Classroom. This said, it is no surprise that Alice has created a Google Chrome extension purposed for use with Google Classroom. The extension is called Alice Keeler Open Side By Side and it's incredibly simple and powerful.
Once the extension is installed, you can right click any link and open it in a new window by clicking on the newly added"Open Side By Side" option in the right click dropdown menu.
This is a wonderful tool for teacher who want to open two windows at once when grading student work. It can also be utilized by students who would benefit from opening a new window, so they can have both the assignment instructions in front of them, as well as the window with their work in front of them.
My opinion: give this extension a try. Chances are, you will find multiple uses for it in your classroom!